Peru’s largest and most important protected area is the massive Reserva Nacional Pacaya Samiria, a vast 2.08 million hectare (8,030 square miles; roughly the size of New Jersey or El Salvador) swath of pristine rainforest threaded with endless waterways. The two most important, forming the borders of the roughly triangular reserve, are Maranon and Ucayali Rivers.
Where Pacaya Samiria narrows to a point, at their celebrated confluence, the official birthplace of the mighty Amazon. Climb the viewing tower for the iconic photo. Visitors to the reserve must come with a guided tour.
The Pacaya Samiria begins about 183km (114mi) south of Iquitos, a trip that can be done entirely on the water, or more quickly (if less scenically) by driving along the 90km (56mi) Iquitos–Nauta Highway, to the Port of Nauta. Scores of different tours are on offer, following the Maranon, Ucayali, and other assorted waterways through the thick vegetation and canyons.