The Amazon is a river, and a region, of superlatives. It's the world's largest river when measured by volume. With 209,000 cubic meters (55 million gallons) of water flowing into the Pacific each second, it's five times the size of the Congo, the next largest river. The basin it drains is some 7 million square kilometers (2.7 million square miles), making it the largest drainage basin in the world. (By comparison, the contiguous United States is roughly 8 million square kilometers, or 3.1 million square miles.) What most impresses visitors to the Amazon, however, is rarely these numbers. Instead it's the area's cultural and natural riches and the experience of seeing the rain forest extend in every direction.
As you travel along the length of the Amazon, you'll call at villages that are not just geographically remote, but are far from contemporary culture as well. Some 400 indigenous peoples live in the Amazon, as they have for centuries. On the same journey, you can visit the 19th-century opera house at Manaus and the colonial-era churches in Santarém, Macapá and other cities. Biologically the basin is home to some 10 percent of all the world's known animal and plant species. From jaguars to macaws and pink dolphins to glass frogs, the Amazon is an area of astounding and unique biodiversity.