Adrienne:  This evening's lecture is co‑hosted by the University of Melbourne and the Museum Victoria. It's part of the Aztecs exhibition which features over 200 cultural treasures from Mexico's major museums.

But before we begin, I would like to acknowledge the traditional owners of the land on which we gather this evening. These are people of the Kulin Nation and we pay respect to the elders past and present.

In this series of special lectures showcasing at Melbourne Museum and also at the University of Melbourne until the end of July, the University of Melbourne and the Museum of Victoria, two of our most iconic and important educational and cultural institutions, have combined together their expertise and experience to provide a background and an in‑depth look at the Aztecs and the Aztecs' exhibition here at Melbourne Museum.

Tonight's lecture, the first in the series, is called, "Searching for Aztecs in Mexico City." It will be presented by Dr. Patrick Greene.

Dr. J. Patrick Greene OBE is an archaeologist who excavated the site of the medieval monastery in Cheshire in the north west of England in the 1970s and 1980s. As our beloved Chief Executive Officer here at the Museum of Victoria since 2002, he spent time in Pompeii as the Museum prepared for a major exhibition in 2009.

He also went to Egypt to visit archaeological sites in readiness for the amazing Tutankhamun exhibition. His most recent visit was to Mexico City, which occupies the site of the Aztecs' remarkable capital city, Tenochtitlan.

Without further ado, please join me in welcoming Dr. Patrick Greene to the stage.

Dr. Patrick Greene:  Thank you Adrienne, and I would also like to welcome everybody here tonight for this lecture. It's a pleasure once again to be working with the University of Melbourne, who have been partners with us since in fact, the Pompeii exhibition in 2009.

It's been a terrific relationship, and one which we hope will continue. I'm sure it will. I too would like to acknowledge the traditional owners of the land on which we have gathered. I will be talking at some stage of this lecture about indigenous people on an entirely different continent on North America.

Mexico is of course, is in North America. A lot of people think it's in South America, but it's not. I'm going to try and transport you there as a result of my trip to Mexico in October last year. I went there of course, in preparation for us hosting the Aztecs Exhibition here at Melbourne Museum. I hadn't been there before, it was my first visit. But, as an archaeologist, of course it had been on my wish list for a long time.

There's such a rich heritage of cultures in Mexico, such as the Maya, Toltecs, Mixtecs, Zapotec. They act as a powerful lure to draw anyone interested in the past to Mesoamerica. In my case, it was the Aztec civilization in the Central Valley of Mexico that was my focus. I was keen to see what remains of the Aztec capital, Tenochtitlan. Mexico City now occupies the site.

I wanted to know what happened in the area before the Aztecs arrived, that might have influenced their culture and beliefs. I was also interested to find out what legacy of the Aztecs remained nearly five centuries after their defeat and conquest by Cortez in 1521.

In this lecture, I will tell you what I found, and I'll also show you using photographs that I took while searching for Aztecs in Mexico City, also visually what I found.

First impressions of Mexico City are not promising as far as finding archaeological traces of the pre‑Hispanic civilization. It's a vast, noisy, exciting place with lots of people. About 22 million people live there, which is of a similar order to the entire population of Australia, and it has the traffic jams to match.

However, as I discovered, if you look hard enough it's surprising what you find. For example, there's the archaeological site of Cuicuilco which lies on the southern side of the conurbation, originally on the shores of Lake Texcoco. It's Mexico City's version of Pompeii, buried as a result of a volcanic eruption in about 400 AD, not by ash as happened to the Roman town, but by lava, up to 10 metres thick, a formidable barrier to archaeological excavation.

The temple, circular in plan, appears to be built in about 600 BC to represent a volcano with a crater in the middle. The crater was being excavated when I visited.

While a circular plan, as opposed to a square or rectangular plan, was different to the later temples that I visited, the representation of a mountain was common, as was the flight of steps rising up the side of the temple, which you can see in this image.

It's not known for certain what happened to the inhabitants of Cuicuilco when they had to abandon their town as it was swallowed by flows of lava, but one theory was they moved to Teotihuacan, and this model shows the layout or part of the layout of that city.

I had the opportunity to visit the enormous archaeological site that's about an hour's drive northeast of the centre of Mexico City. It's a world heritage site and it's easy to see why UNESCO placed it on the register. The city covered an area of 20 hectares and estimates of its population ranged from 100,000 to 200,000 people, a very big city.

The focus for most visitors is the area of temples. Huge, huge pyramids that command the view as soon as you approach the site.

It isn't an Aztec site, but it made a great impression on the Aztecs, who regarded it as the city of the dead. Many of the gods who were worshipped by the Aztecs were also venerated in Teotihuacan, centuries before the Aztecs arrived.

Teotihuacan appears to have been founded in about 100 BC and it reached its zenith in about 650 AD, a long history but it was abandoned around 750 AD. There's some evidence which points to an uprising of the populace against the elite. Some of the elite houses and temples show signs of burning.

It was about five centuries later that the Aztecs came across the abandoned city as they journeyed through the valley of Mexico in search of a place to settle. They had left Aztlan, hence the name Aztecs. They called themselves the Mexica in the mountains to the far north of the valley of Mexico in the early to mid-twelfth century AD.

It's important to get that time frame we're talking about. We're talking about the 12th century to the 16th century, of which the latter two centuries are the centuries of the Aztec empire.

Much more recent than many of the civilizations that we've covered in our exhibitions here. Much more recent than many of the civilizations of Mesoamerica.

The site was explored, Teotihuacan, in the 19th and 20th centuries. But discoveries continued to be made. I visited this temple, which is devoted to Quetzalcoatl the feathered serpent, who was one of the dominant deities of Mesoamerica and who was later embraced by the Aztecs as an important god in their pantheon.

The temple is located in a large courtyard known as the citadel. Part of the original structure of the period has carved masonry surviving in situ.

Snakes with feathered bodies, representing Quetzalcoatl writhe in panels that have carved symbols such as seashells and references to other gods such as Tlaloc, the god of rain and of lightning.

A fascinating discovery was made a few years ago, quite by chance. A tunnel that runs underneath the temple has been explored by a robot camera and excavation is continuing. The cover you see in this photograph is the photo over the virtual shaft that goes down from which this horizontal tunnel runs.

In that tunnel have been found jade masks, pottery, and other finds. Also, tiny pieces of sparkling minerals are being recovered by sieving. This suggests to archaeologists that the tunnel represents the waters of an earlier world, with the sparkling minerals on the walls to give the impression of water.

It's also important to understand that for the Aztecs, this world was the fifth world, of which the four previous worlds had all been destroyed, and the sun had failed to cross the sky, and that all of them had originally originated in the sea and underwater.

Other excavations of this temple have revealed skeletons of people sacrificed during one of the stages of construction of the pyramid. This display is in the Museum of Anthropology and History in Mexico City. It provides a vivid image; a row of skeletons displayed as they were found in the excavation together with other burial goods.

This practice of sacrificing people as the temple was inaugurated, and then extended at later dates, continued right through to the Aztec era.

The citadel is located alongside the Street of the Dead. That has a north‑south alignment. We're looking south here. Visible to the south are mountains, the form of which is echoed by the temples, as I think you can clearly see. Midway along the eastern side is the temple of the sun.

This truly enormous pyramid has a base that measures 225 metres on each side, and as you can see, five stages and a staircase leading to the top where a temple once stood.

It's 65 metres in height, and visitors to the site can climb to the top. You can see some on the top there. But at the altitude of Mexico City, that can prove quite a challenging task. The view is worth it, as the plan of the ceremonial zone is much easier to visualize looking down from above.

The Street of the Dead is lined with temples, and it culminates on its northern end with another enormous pyramid, the Temple of the Moon. That's clear to see on this image.

There are areas of houses of the elite, and tantalizing for the archaeologists, mounds covered in vegetation of yet‑to‑be‑explored structures, and you can see those in the foreground. I was tempted to get out my spade. I visited two of the elite houses. They were extensive structures with a variety of rooms, and each house had its own temple. There are lots and lots of temples at Teotihuacan.

Like the major temples, these show evidence of reconstruction at various times. The west plaza complex demonstrates this very clearly with a raised floor level installed above the earlier layout. You can see the raised floor where the excavation has gone down to reveal those steps of the earlier, smaller temple. Like the big temples, the smaller temples would be added to by successive owners and get bigger and bigger.

You can see the temple steps flanked by carved heads of split‑tongued snakes, painted decoration ‑ you could just make that out in the lower part ‑ survives as a reminder that most of the buildings were covered in stucco with rich imagery. That's very apparent in the so‑called Palace of Quetzalpapalotl, where remarkable paintings have been preserved and conserved.

The work of conservation was continuing when I visited, and I got to meet the conservators, employees of INAH, which is the organization responsible for looking after Mexico's archaeological sites, of which there are very many ‑ 20,000 of them, in fact. And they also look after 200 museums. It's a very important organization, and they are a strong partner with us in presenting the Aztecs exhibition here today.

It is, in fact, their 75th anniversary, and this accounts for the quality for the objects in the exhibition that they prepared to lend to us.

They're doing two exhibitions this year ‑ this one and the other one is going to Brazil to coincide with the World Cup, and that's on the Maya. Doing the conservation is very delicate work, as the stucco is such a thin fiber layer on the wall surface. I was able to see murals with creatures such as a jaguar blowing a feathered conch shell.

This won't be immediately apparent that it's a jaguar blowing a feathered conch shell unless you are a scholar studying Teotihuacan imagery. But that's what it is.

Jaguars are very, very important in the mythology of the Aztecs and their forbears. Another feature that was pointed out to me was the presence of pits dug through the floors of the building. I wrongly assumed that this was the result of looting in the recent past, but that's not the case. The pits were dug in the distant past by the Aztecs searching for objects that they venerated in consequence of their association with the City of the Dead.

These were often presented as offerings in the Aztec temples, particularly in those foundation deposits that I've already referred to. And there are examples of that in our exhibition. In fact, the Aztecs are described as the first archaeologists. I was on the trail of the Aztecs, gradually understanding some of the influences that impacted upon them from past cultures in the valley of Mexico.

In Mexico City itself, I came face to face with the spiritual heart of the empire, the Templo Mayor. Now, in this model, the Templo Mayor is the very large building at the back with the two shrines or smaller temples on top, and other important public buildings relating to the administration of Tenochtitlan here in the foreground.

It's astonishing to think that until the 1970s almost nothing was visible of the city that was described by one of Cortez's men in this way. "We were amazed and said it was like the enchantments." Tenochtitlan had been so thoroughly destroyed and then covered by colonial‑era buildings that it might never have existed.

This is an 18^th century plan of Mexico City. It's on an island, and beneath that, already at that stage, completely covered, was the Aztec city of Tenochtitlan. It's a growing city. It's growing out towards the edges of the lake.

It's also a challenge to think of the Aztec city surrounded by water because the island in the lake, and indeed the lake itself are almost entirely covered by the modern Mexico City which has major subsidence problems as a result.

The Aztecs reached the surrounding lands by way of broad causeways. Today you simply drive in or catch the metro. But in 1978, a massive round carved stone was uncovered during building work near the cathedral and near to Zocalo Square.

The stone depicts the moon goddess Coyolxauhqui and she has been dismembered. The more you look at this the more you can see the body parts scattered around it and also skulls representing obviously death. Coyolxauhqui and her dismemberment are part of the foundation myth of the Aztecs in which she was vanquished by her brother Huitzilopochtli, the Aztec's main god, for trying to prevent his birth.

The discovery led to an archaeological excavation that continues to this day, in which the remains of the great temple that stood in the sacred centre of Tenochtitlan have gradually been uncovered and I was fortunate to be invited to meet the archaeologists and go behind the scenes.

Compared to the pyramids of Teotihuacan, Templo Mayor looks rather unprepossessing at first sight, a jumble of walls, discolored by the often-polluted air of Mexico City. Look more closely however and what emerges is the epicentre of Aztec relief, in a world in which the gods who had sacrificed themselves, required sacrifice on the part of the people, to ensure stability and property.

Templo Mayor began as a pyramid but grew and grew in size as seven successive Aztec leaders added to the structure. Because they were bigger and higher, the later phases have been damaged considerably.

There at the centre of the second phase pyramid built in the period 1375 to 1427 were two temples on top. One was devoted to Huitzilopochtli, the god of war, and other to Tlaloc, the god of rain and water. In this image, you can see those two temples on the drop there on the left‑hand side and look towards the right and you'll see the stone.

Over that stone, individuals were stretched backwards for the priest to slice into the body with an obsidian blade to remove the beating heart. The blood poured down the steps and the discarded body tumbled down them. I should have said this is R‑rated.

This was the bloody reality of the way in which the gods were appeased in Tenochtitlan and many, many people met that fate. Often, but not always, it was warriors captured in battle that ended their days sacrificed to ensure that the sun will continue to traverse the sky, that rain would fall and that crops would be bountiful.

It was assumed that every Aztec male will grow up to be a warrior until proved otherwise. The Aztecs extended their empire through conquest in which battles were fought in such a way that warriors are not to kill their opponents but to maim and then capture them.

Success was rewarded with a rise up the ranks and each successive battle if you got a prisoner, you worked your way up as far as the elite eagle warriors. Now the Aztecs actually, their battles, particularly when they entered a triple alliance with two other city states, were very successful and they extended the empire to such a point that something like 400 city states were subject to them.

Now what they did was they left the power structure in place when they defeated one of these states but insisted that they paid tribute to the central government and the central establishment in Tenochtitlan.

So right at the top of the warrior scale were the eagle warriors. This is one in the Templo Mayor Museum and we have another one, also from Templo Mayor that is in our exhibition. Sacrifice and the deposition of offerings also accompanied each enlargement of the pyramid. I was invited to see the latest finds from the excavation such as the skulls that had holes in the crania, where they had been displayed on racks.

Also incense-burners, this is one in the process of conservation. We have another one, a twin of this one, displayed as part of the Aztecs exhibition. In fact, it was anticipated that 52 of these were going to be found in this location. 52 is a very significant number in the Aztec calendar, I will come to that a bit later.

The Museum at Templo Mayor has an extraordinary wealth of finds from the site including many offerings often placed in stone boxes for the purpose. One found behind the rear facade of the temple contained human skulls, jewellery, sea shells, the bill of a sword fish, obsidian blades, and carved stones.

The museum has extraordinary exhibits from the archaeological excavations. You are seeing the figure of the eagle warrior and Mictlantecuhtli, the god of the underworld. We have another ceramic image or feature of Mictlantecuhtli in our exhibition, a twin of this one.

If you see he is standing there with his ribs exposed, that's his liver hanging out, which was supposed to be where the soul was located. But once you've met Mictlantecuhtli, having gone down through the various layers to the underworld, you were reaching your destination. So not quite as terrifying as he looks.

Is Templo Mayor the only place in Mexico City where it's possible to find remains of the Aztec civilization? I continued my search in the Park of Chapultepec. The name is encouraging as it has a name in the Aztec language Nahuatl meaning hill of the grasshopper. It's one of the largest urban parts in the world and is a delightful landscape of forests and some lakes.

There, I came across traces of a hydraulic system that supplied Tenochtitlan with fresh water, built between 1466 and 1478, a very, very advanced system. The so-called Baths of Moctezuma are part of that system.

I found a second place where excavations have revealed heart of the system. I also found a much more recent memorial to the man who organized the water supply, Nezahualcoyotl who was the ruler of the city state of Texcoco, which was allied to Tenochtitlan. He was a renowned poet, as well as an engineer and a military strategist and clearly very effective as a water engineer too.

The joint statue and the fountain were installed in his memory in the mid-20^th century. He built aqueducts to take water from the mountains and from Chapultepec Hill across the lake into Tenochtitlan, a very impressive feat at a time when most cities in Europe lacked effective water systems.

He also built a barrier in Lake Texcoco to prevent flooding which had been a real problem and to stop saline water mixing with fresh water. He is also credited with planting thousands of trees, especially the Ahuehuete in creating a beautiful park around Chapultepec for the use of the emperor.

A giant dead Ahuehuete stands as a memorial to the Aztec era. It's associated with Moctezuma and was reputedly planted in 1460. Elsewhere in Chapultepec Park is another fountain with Aztec associations. Next to the pumping station that supplies modern Mexico City with water is this fountain designed by Diego Rivera, the renowned mural artist, and inspired by the Aztec god of water Tlaloc.

The central part of the fountain was restored recently. You can just make out water squirting out of his head and then splittering and splattering down into the water surrounding. This part has been restored, but other parts built to resemble the feathered god Quetzalcoatl are in the process of restoration and that awaits completion.

Right in the centre of Chapultepec Park is a hill of volcanic rock that rises abruptly from the surrounding woodland. On the steep eastern side, I thought I could see carvings that appeared to be pre‑Hispanic in their design. As I looked closer, I thought I was looking at part of a giant carved figure, and you see that smooth rock there. To the left of it you can also see some Aztec symbolism, albeit that at some stage people have tried to peck at it and obliterate it.

I subsequently found that my supposition was correct. When the Spanish arrived, they found that the rock had been carved with enormous figures of Aztec emperors beginning in the 1460s. Invaders spotted the strategic potential of Chapultepec Hill and established a castle on the top.

Having the images of the Aztec Emperor staring boldly from the rock was unacceptable to the new regime, and they were largely destroyed using gunpowder. I'd seen the remnants. How magnificent it would have been if it survived. And they went all the way through to Moctezuma. The Emperors started to get the figures carved when they had premonitions of their own death to be sure that they would be remembered after they died.

The National Museum of Anthropology and History is located close to Chapultepec Park. It's a magnificent museum with remarkable collections and I went there on three occasions. The galleries surround this rectangular courtyard with this breathtaking roof over it. And they are arranged on two levels.

The ground floor has archaeological displays devoted to the main pre‑Hispanic cultures including Teotihuacan and of course the Aztecs. On the upper floor are wonderful ethnographic displays that relate to pre‑Hispanic cultures such as this one about the cultivation and uses of maize.

One of the roles of the museum is to illustrate the fact that although people such as the Aztec were defeated by the Spanish, accompanied by diseases that devastated the population such as smallpox, indigenous people continue to live in Mexico and continue to practice some at least of their traditional activities.

In fact, there are one and half million speakers of a form of Nahuatl, the original Aztec language today. The Aztec wall is a highlight of a museum with many highlights. It's dominated by the massive circular carved stone you can see at the back of the gallery on this image. And that shows the Aztec calendar.

There were two intersecting calendars that govern both daily and spiritual life, one of 365 days and the other of 200, the latter being the spiritual one. Together they formed a period of 52 years, that's where that number 52 comes from, the conclusion of which was regarded a time of great uncertainty, and it was a time of considerable sacrifice.

There were also during the 365-day year comprised 18 months of 20 days and five spare days, those two regarded as a time of great danger, and all the fires were extinguished until it was proved that the sun would rise again, and people could light them again, and that was accompanied by sacrifices as well.

Another impressive carved stone is this one, a circular stone thought to have been used in another sacrifice ceremony in which a captured warrior engaged in a fight with four better armed Aztec warriors. The outcome was never in doubt. His blood collected in a hollow in the centre and flowed along the channel that you can see down the edge of the block and into the earth.

The displays also we view much about the daily life of the Aztecs, much more cheerful scene such as the market that was the centre of their trading activities which were very considerable and went across the whole of Mesoamerica. It's an excellent model and you can see just in this small portion of it a wide variety of things that were available for sale.

We have a version of it in our exhibition here which those of you have already seen it will have looked at and it's a marvelous illustration of this trading activity.

It was a very well-organized state. There were special officials, for example, to make sure that trading was carried on in a fair manner and good order was maintained and that the merchants had the proper authorizations to go beyond Tenochtitlan to do their trading across the empire and beyond it.

Well, the arrival of the Spanish marked the end of Tenochtitlan which was comprehensively demolished to make way for the new city and of course it was accompanied by the suppression of Aztec religious practices.

Christianity provided a substitute. A son sacrificed by his father in a painful death on the cross - that resonated with the people whose gods would sacrifice themselves and to require blood sacrifice to ensure the order of the universe was maintained. Next to the partly demolished Templo Mayor, the Metropolitan Cathedral was constructed.

The new arrivals used stones from the Aztec buildings for their constructions and even turned some into baptismal fonts as could be seen in the ethnographic museum, and then the appearance of a young indigenous man of our Lady of Guadalupe gave rise to a new object of veneration and pilgrimage which continues to be to this day.

In fact, Our Lady of Guadalupe has become a national symbol of Mexico. When Father Miguel Hidalgo called for independence from Spain in 1810, a banner with the image of the Virgin was carried by his supporters, and you can see in this mural from the National Museum of History there is a light‑colored banner behind Father Hidalgo and you could just make out the image of the Virgin.

On the top of Chapultepec Hill is a building that has served as a range of functions including a military officer training facility, the palace of Emperor Maximilian for that brief time that Mexico was an empire, and today the National Museum of History.

The story of Mexico is tumultuous. Fighting wars with external enemies, rising in revolt against the Spanish empire, and experiencing revolutions and civil wars. The museum shows that history, vividly illustrated with mural paintings such as the one we've just seen. So, what of the Aztecs?

The Spanish empire tried to forbid into marriage between European and indigenous people. But as this painting in the museum shows that was completely ignored and all sorts of different relationships quickly grew up, including with Cortez himself. As a result, most people in Mexico are Mestizos with a heritage that includes both cultures.

It is a complex situation in which the poorest people in Mexico in the furthest parts of the country are the descendants of the pre‑Hispanic inhabitants and I was told that there is widespread racism.

Despite this, it's not hard to find references to Mexico's Aztec heritage, starting of course with the name derived from Mexica as the Aztecs called themselves. For flag adopted in 1821 has as its centrepiece an eagle sitting on a cactus with a snake in its beak.

This, in the Aztec's foundation myth, was what their god Huitzilopochtli instructed the Mexica to find as the marker of the place where they should build their settlement after their years of wandering, and they saw it on the lake on the island in the lake of Texcoco and built Tenochtitlan there.

Diego Rivera is one of those who was active in urging Mexicans to embrace their pre‑Hispanic past and in the studio he shared with Frida Kahlo, now a museum, are many artifacts that provided inspiration. His magnificent murals in the National Palace feature vivid images of Aztec life including brutal subjugation following the Spanish conquest.

And as you look particularly to the upper part of this mural, you will see some of that subjugation being carried out in a particularly brutal manner. This was a piece of honesty about Mexico's past that resulted from Diego Rivera's amazing murals.

We have another of his murals represented on a very large scale in the exhibition showing his version of the market scene, but it's not only in the National Palace that you find his work, even in the Olympic stadium there are references to Aztecs in this relief sculpture also by Diego Rivera that features Quetzalcoatl along the lower edge.

You can just make out the snake's head and the feathered body and on the top you can see where the Olympic flame once was lit. Well, I found a different kind of art in two museums set up by a foundation established by Carlos Slim, the Mexican entrepreneur who is reputed to be one of the world's richest people.

Both of the museums he set up were called Museo Soumaya named after his wife. And they have a very broad range of art from Rodin, Renoir, up to the present day. But they also include lithographic prints produced from the 1950s to the 1970s by the Galas Printing and Publishing Company, another company that he acquired.

Aztec images predominate presented in an idealized form with images that include eagle warriors, romantic scenes and beautiful women, some muscly men too playing the traditional Aztec ball game, which was another brutal experience. I can tell you the rules the afterwards if you want to ask me. The artist was Jesús Helguera and his creations in the form of calendars once decorated tens of thousands of homes across Mexico, so this is popular art.

One of the Soumaya Museums is in fact located in the restored buildings of lithographic print works where these print works were once produced. The other is a spectacular creation clad in aluminum tiles that has been open for a couple of years.

His foundation's motto is 'Art for All' and both museums are free to enter. Most recent imagery that was inspired by Mexico's Aztec past that I saw was in an exhibition entitled 'Black Humour with a Green Tinge'. About 70 cartoons were displayed on the railings of Chapultepec Park all with an environmental message drawn by a cartoonist called Victor Solaz.

In one, an Aztec emperor is looking down from a temple at Lake Texcoco and saying to his companion that the gods have given him a worrying vision of the future in which the lovely lake has disappeared, and the dry ground resembles a giant gruyere cheese. This relates to the fact that the city is sinking as I've mentioned, into the bed of the former lake with excessive pumping of ground water exacerbating the problem.

In another, a boatman is punting his boat on wheels along the dried-out bed of the lake Xochimilco. So, what of Lake Texcoco that once surrounded Tenochtitlan? On my last day in Mexico City I visited Xochimilco where some vestiges remain.

A popular activity is to hire boats, one of these lovely multicolored boats, go out in the water, listen to mariachi bands who are also on boats, and eat quesadillas and other dishes, also prepared by cooks on their boats. And yes, I did eat a quesadilla, two in fact.

Alongside the water are lovely market gardens with vegetables and flowers growing on chinampas. This was the horticultural technique that the Aztecs invented, the so called floating gardens. Floating gardens is in fact a misnomer as in fact stakes were driven into the lake bed and the rectangular space inside was filled with mud and soil and in the process the canals that crisscross Tenochtitlan were created.

This is a model in our exhibition here again from Templo Mayor.

Trees were planted to help hold everything together. The Aztecs found they could grow as many seven crops a year with the abundant sunshine and water and this is one of the factors that led to the wealth of their empire. Despite the destruction and disease that the Spanish conquest caused as I have described there is a strong legacy of Aztec culture to be found in Mexico City.

However, it extends far beyond Mexico. For when we eat avocados, tomatoes, chillies and chocolate we are enjoying foods that the Aztecs grew and enjoyed and by using those names we are speaking their language Nahuatl in 21^st century Melbourne.

Before I finish I must mention another plant that was crucial to the Aztec's way of life, maguey, which is a form of agave which you can see growing behind me here. This drought resistant plant is found in many varieties in Mexico and the Aztecs used it for many, many things - the fibre for food and cloth and the sap, it has very sweet sap, in cooking and that could be fermented as an alcoholic drink.

It had medicinal properties and even the sharp spikes were used by the Aztecs to prick naughty children as a form of punishment. You can see impressive displays of Mexican agave plants in the Royal Botanic Gardens in Melbourne. The Aztec's staple food crop was maize, and they used it very similar ways that we do today, the tamales, the tortillas eaten in every household.

So, I enjoyed searching for Aztecs in Mexico City and I was pleased to discover that there are many ways in which the fascinating culture has left a mark today excepting of course the sacrifices. Now the Aztec exhibition here is providing an opportunity for many thousands of people in Australia to come face to face with the glories and the tragedies of one of the world's great empires.

Well, that completes the lecture. Do come back to other lectures in the series.