Tenochtitlan Architecture: The Aztec Floating Gardens & Aqueduct System

A 1945 painting of the Aztec city of Tenochtitlan highlights the floating city’s unique aqueduct and irrigation systems. (Source)

March 15, 2019 ~ By Shari Rose                             

Updated January 8, 2022

From floating gardens to an advanced aqueduct system, Tenochtitlan’s architecture sustained hundreds of thousands of Aztecs until Spanish conquistador Hernán Cortés stepped foot on shore

Founded in 1325, Tenochtitlan was a hub of architectural and agricultural innovation, allowing the Aztecs to develop technological advancements unseen in other civilizations. After the fall of the city, modern-day Mexico City was built atop the ruins of Tenochtitlan, sealing away the Aztec aqueduct system below the earth. From floating gardens atop broad lakes to aqueducts that carried plague-free freshwater to homes and buildings, Tenochtitlan architecture utilized a range of innovative technologies that supported its staggering population growth and separates it from any other major civilization in the Western Hemisphere.

How Aztec Architecture Gave Tenochtitlan Its Nickname, “The Floating City”

Map of the Aztec city of Tenochtitlan (Source: Wikimedia Commons)

The actual size of Tenochtitlan is believed to be about five square miles, situated on the western side of Lake Texcoco. The lake itself was connected to four other smaller lakes, some freshwater and some saltwater. 

So how exactly were the Aztecs able to construct Tenochtitlan on top of a lake? Because Lake Texcoco was fed through springs, and not flowing rivers, the lake was shallow and its waters calm. Over time, the Aztecs discovered how to create irrigation systems like aqueducts and build artificial islands on that lake and surrounding bodies of water. These feats of Tenochtitlan architecture eventually helped support the largest concentration of people found in Mesoamerica at the time. 

At 2,100 square miles, Lake Texcoco was not an easy environment to make livable. But the Aztecs converted much of the nearby freshwater lakes and swampland into floating gardens, called chinampas, and enjoyed multiple harvests per year.

Chinampas: Aztec Floating Gardens

When the Aztecs first established Tenochtitlan, they faced many challenges with growing food. There was erosion and flooding to contend with, as well as loss of soil fertility and steep slopes that didn’t support plant growth. Arguably, their biggest obstacle was the sprawling swampland in the region’s lakes and rivers.

So, how did the Aztecs figure out a way to feed approximately 500 people per square mile in Tenochtitlan with this kind of environment? Through constructing chinampas, or “floating gardens,” Tenochitlan’s architecture would separate itself among other civilizations of the time by successfully growing food on a non-sedimentary lake.  

Modern floating gardens, called chinampas (Source: Wikimedia Commons).

Floating garden construction was a straightforward process achieved with simple tools and human labor. First, using a series of wooden stakes and plant material, Aztecs fashioned rectangular plots into the lake bed. Chinampas were uniform in size, with most at 98 feet long and eight feet wide. These measurements ensured that canoes could fit between each floating garden. Aztec laborers then filled each chinampa with soil and vegetation until the pile reached the lake’s water level. Finally, they planted willows around the plots to keep the floating gardens in place.

In the early days of Tenochtitlan, flooding was a significant problem for these lake-dwelling gardens. To control the flow of water to the chinampas, the Aztecs built a complex aqueduct and irrigation system that included dams and gates to control water flow. When the dry season hit in summer, laborers physically carried water to the plots. In total, the Aztecs converted 30,000 acres of marshland into farmable floating gardens.

Through this agricultural feat, the Aztecs didn’t have to rely on Earth’s natural seasons, and reaped multiple harvests during the year. The success of chinampa construction supported Tenochtitlan’s booming population, allowing it to become the most densely populated region in Mesoamerica. 

Floating gardens are just one example of the Aztecs’ superior architectural prowess. Another method found new use of the environment’s abundant water supplies with Aztec aqueducts.

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Aztec Aqueducts: Tenochtitlan’s Incredible Feat of Architecture

The Chapultepec Aqueduct, a work of Tenochtitlan architecture still found in Mexico City today. (Source: Wikimedia Commons)

The Chapultepec aqueduct was the primary source of freshwater to Aztecs in Tenochtitlan. Carrying water from the Chapultepec springs, this aqueduct was a major architectural achievement because of its twin-pipe water distribution system. With two pipes transporting water, the Aztecs could simply divert water from one pipe to the other, should one become dirty or damaged. As a result of this innovative architecture, Tenochtitlan always had access to freshwater, a luxury that many other civilizations of the time never achieved.

The Aztecs also built a wooden walkway along the length of the Chapultepec aqueduct so it could be easily cleaned and maintained. Unlike the Roman aqueducts that carried pollution and disease, Tenochtitlan architecture ensured that Aztec aqueducts were not plagued with, well, the plague. With the walkway along the major aqueduct, laborers consistently cleaned and repaired this lifeline for the city. The water from the Chapultepec springs was used mainly for cleaning and bathing, as the Aztecs are widely believed to have bathed twice a day.

In 1449, extreme flooding destroyed an earlier version of the Chapultepec aqueduct. The Aztecs then rebuilt the aqueduct with stone masonry, a much more resilient material. It rested on multiple, human-made islands for stability. This feat of Tenochtitlan architecture and agriculture ensured that the Aztec’s crops and people would be well cared for with a virtually endless supply of fresh water.  While new construction of the Chapultepec aqueduct was completed along its original path some 200 years later, the only remaining piece of the colonial aqueduct can be found near Metro Sevilla in Mexico City.

After Spanish conquistador Hernán Cortés and his men were welcomed by the Aztec people, they were invited to explore the city. In his personal diary, Cortés noted how interwoven the aqueducts and canals were on the streets of Tenochtitlan. “All the streets at intervals have openings, through which the water flows, crossing from one street to another,” he wrote. “And at these openings, some of which are very wide, there are also very wide bridges, composed of large pieces of timber, of great strength and well put together; on many of these bridges ten horses can go abreast.”

Though it was the lifeblood that fed Tenochtitlan, the Chapultepec aqueduct proved to be the Aztec’s weakest link with the arrival of Spanish conquistadors. During the Spanish conquest, conquistadors choked off the aqueduct’s access to the city, destroying the irrigation system, and its residents quickly began to starve. 

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Aztecs Meet Spanish Conquistadors in Tenochtitlan

Montezuma of the Aztecs (Source: Wikimedia Commons).

By the time Spanish conquistadors entered the royal palaces of Tenochtitlan, the city boasted between 200,000 and 300,000 residents. And unlike other societies at the time, most Aztecs were not farmers. Rather, they were merchants, craftsmen, warriors, clergy members, and city administrators. In the most bustling part of the city, Spanish conquistadors were astounded by the sheer volume of goods transported into the city by canoe and aqueduct.

When describing the economic centers of Tenochtitlan, Hernan Cortes wrote, “This city has many public squares, in which are situated the markets and other places for buying and selling. There is one square twice as large as that of the city of Salamanca, surrounded by porticoes, where are daily assembled more than sixty thousand souls, engaged in buying, and selling; and where are found all kinds of merchandise that the world affords…”

In this same letter he wrote to the king of Spain, King Charles I, Cortes recounted all manner of goods and products in the city, from gold and silver, to birds and game, apothecary herbs and fine stone goods. “Painters’ colors, as numerous as can be found in Spain, and as fine shades,” Cortes wrote. “Deerskins dressed and undressed, dyed different colors; earthenware of a large size and excellent quality; large and small jars, jugs, pots, bricks, and an endless variety of vessels, all made of fine clay, and all or most of them glazed and painted.”

Streets were divided by goods that Aztec merchants had for sale, with whole avenues dedicated to pottery, fish and fowl, jewels and precious stones. Innovative Tenochtitlan architecture allowed for a diversity of shops and markets in the heart of the city to be accessible by most Aztec inhabitants. 

Fall of Tenochtitlan

In 1519,  King Montezuma II greeted Hernan Cortes and his men in the Aztec palace that boasted unbelievable riches of gold, silver, gems and other precious resources. The Spaniards stayed in Montezuma’s palace for some months, until the Feast of Toxcatl, where scores of Aztec nobility were killed by conquistadors.

In the aftermath, Cortes held Montezuma captive in his palace until he was killed. Because differing first-hand accounts blame one other for his death, we may never know for sure how exactly King Montezuma died in his palace.

However, there are two accounts concerning King Montezuma’s murder that are widely accepted by historians. The first account points the finger at rebelling Aztecs who were displeased with Montezuma’s rule, and killed him with a stoning. A second account contends it was the Spaniards, still holding the king hostage in the palace, who killed Montezuma in their eagerness to take control of the city.

In the bloody aftermath, Cortes barely escaped Tenochtitlan with his life. In 1521, he returned some time later with an army of some 70,000 troops, mostly Mesoamerican warriors from other societies with an interest in taking down the city.

Cortes’ forces destroyed the Chapultepec aqueduct, decimating a key part of Tenochtitlan architecture and starving the city. At the same time, the Aztecs were hit with a smallpox epidemic for which they had no immunity. Warriors were unable to walk, let alone fight in these conditions. Spain declared victory in August 1521, while the remaining armies sought to kill whomever remained alive in Tenochtitlan.   

Legacy of Tenochtitlan Architecture & Aqueduct Systems

The Aztecs are probably most famous for their human sacrifice rituals, but there is just so much more to know about this incredible civilization. Their ability to not only survive, but prosper, in a strange and difficult environment surrounded by water stemmed from technological innovations in irrigation, agriculture, and architecture, most of which the world had never seen before. The Aztecs truly ensured Tenochtitlan was a floating city unlike anywhere else in the Western Hemisphere, forever sealed away beneath modern-day Mexico City.

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