While living in swamps, Aztec priests received a vision from gods telling them to migrate. The Aztecs believed in over 1,600 gods who controlled nature and human life. They built their capital, Tenochtitlan, on an island in a large lake, believing their world rested on a giant crocodile swimming in a sea of water lilies. Aztec education focused on developing warriors since they had a military-based culture and made human sacrifices in religious ceremonies to give strength to the sun god.