The Ucayali River is the main headstream of the Amazon River. It rises about 110 km (68 mi) north of Lake Titicaca, in the Arequipa region of Peru and becomes the Amazon at the confluence of the Marañón close to Nauta city. The city of Pucallpa is located on the banks of the Ucayali.
Confluence of the Tambo (from bottom) and Urubamba Rivers (background right) forming the Ucayali River (background left)
The Amazon River in South America is the largest river by discharge volume of water in the world, and the longest or second-longest river system in the world, a title which is disputed with the Nile.
Satellite image of the Amazon Delta
Old drawing (from 1879) of Arapaima fishing at the Amazon river. The arapaima has been on Earth for at least 23 million years.
Amazon tributaries near Manaus
Amazonas state