The Aztec civilization arrived in central Mexico in the 1100s and settled on an island in Lake Texcoco, where they built the magnificent city of Tenochtitlan. In the 1400s, Aztec warriors began conquering neighboring peoples and extracting taxes. Tenochtitlan was built on floating islands and became the center of the powerful Aztec Empire. The Aztecs had many achievements in medicine, astronomy, record keeping, and schooling for boys and girls. Their religion involved worship of gods and human sacrifice. The Inca settled in Peru in 1200 AD and built an empire that stretched 2500 miles by 1438. They had excellent farming techniques, built extensive road networks, and recorded information using knotted string