The Incas appeared out of nowhere, and within a few decades, their empire developed into the largest empire in the world at that time. They ruled over more than a good 10 million people.
More than 2000 years ago, the Mayans built gigantic cities in the middle of the jungle of Central America. Their inventions, such as the number zero, still shape our lives today.
Within a very short time, the Aztecs created a huge empire. Their metropolis was a perfectly organised floating garden city on the Mexican plateau, the sight of which even enchanted the Spanish.