Aztec ChinampasTo grow enough food for their population, the Aztecs built chinampas, or

artificial islands, in swamps and shallow water.

Inca RuinsThe Inca Empire was a vast kingdom that thrived hundreds of years ago in

South America. One spectacular Inca city was Machu Picchu, located high in the Andes mountains. The abandoned remains of the city, shown here, were discovered in 1911.

Maya CityThe ancient Maya people of southern Mexico and Central America built an

advanced civilization more than 1,000 years ago. Every Maya city had a large public square, palaces, and pyramids topped with temples.

Hanging Gardens of BabylonThe Mesopotamian city of Babylon was one of the most important cities in

the ancient world. This picture shows the Hanging Gardens of Babylon, one of the Seven Wonders of the World. The gardens grew on the roofs and terraces of the royal palace in Babylon.