The Amazon Tall Tower Observatory (ATTO) is a joint German-Brazilian scientific project to understand how central Amazon forest interacts with atmosphere and climate.

At the heart of ATTO is a unique 325-m tall research tower that samples air from an extended region of largely undisturbed tropical forest. Other major infrastructure includes two 80-m towers, canopy walkways, laboratory containers and plots for studying soil and plants that allow researchers access from the deep soil to the air above the forest canopy.

The goal of ATTO is to understand the complex interactions between forest and atmosphere, how they respond to extreme weather events, and the consequences of long-term changes in climate and increased carbon dioxide.