The Spanish couldn&rsquot believe their eyes when they first arrived in Tenochtitlan in 1519. The capital of the Aztec, built in the waters of Lake Texcoco, was one of the largest cities in the world at the time, with 200,000 people living in it. Three causeways led to it across the water canals crisscrossed the city to allow transport by canoe four busy marketplaces supported thousands of traders. At the centre of the city was the pyramid of the main temple surrounded by public buildings and the palaces of the tlatoani or lord, Moctezuma II. One of the chroniclers of the Spanish conquest, Bernal Díaz, wrote, &ldquoI do not know how to describe this first glimpse of things never heard of, seen or dreamed of before&hellipI stood looking at it, and thought that no land like it would ever be discovered in the whole world.&rdquo