Finding Lost Amazon Cities: Discovering an Unknown Ancient Society.

Archeologists found old cities in the Amazon rainforest where at least 10,000 farmers lived around 2,000 years ago. The sites were first seen over 20 years ago, but their true importance was only recently understood thanks to new laser mapping technologies.

These ancient cities were part of a big network of settlements and roads, hidden in the forest near the Andes mountains. The area was called a 'lost valley of cities' because of how many settlements were there.

The people who lived there, known as the Upano, built homes and special buildings on big mounds of earth. They had big roads and farmlands with systems to drain water.

It's hard to know exactly how many people lived there, but guesses range from 10,000 to maybe 30,000 people. This suggested they were a very complex and organized society.

Building everything they had without using stone, but rather mud, showed they had a well-organized way of working together. Recent discoveries show the Amazon was home to many diverse peoples and societies, not just small, scattered groups.