The Aztecs were a very interesting group of people. They were a small, nomadic Native American tribe who lived in northern Mexico. The Aztecs called themselves Mexica or Tenocha. During the 12th century, they migrated all the way down to the valley of Mexico. They made their capital at Tenochtillan, an island, in the middle of Lake Texcoco. The Aztecs built temples, public buildings and homes in their city. They were also very smart. They built causeways of stone across the Lake to other islands to travel upon. Also, the Aztecs constructed an aqueduct to carry water from the river that was 4 miles away, to their city. The Aztecs were also great warriors. While constructing their city, they fought to gain new pieces of land. At the end of the 15th century, they ruled over much of what today is modern Mexico.