Manaus is the capital and largest city of the Brazilian state of Amazonas. It is the seventh-largest city in Brazil, with an estimated 2022 population of 2,063,689 distributed over a land area of about 11,401 km². From Wikipedia
The visit is part of Biden's Latin America trip, coinciding with upcoming APEC and G20 summits amidst a looming shift in U.S. climate policy under Trump.