Adapted from a 2015 article in Cruise Critic by Emilie C. Harting

It’s no accident that the Amazon is called mighty. The second-longest river in the world, it flows north and east 4,345 miles from its source high up in the Peruvian Andes, through Peru and Brazil, to its mouth on the Atlantic Ocean. On the way, the Amazon also cuts through a small section of Bolivia. The watershed around it includes the largest tropical rainforest in the world, and a variety of indigenous tribes.

Manaus, roughly in the center of the blue line on the map,  is the center for Amazon travel in Brazil, with flights coming from Miami, Rio de Janeiro and Europe. A number of the cruise lines departing from Florida to South America, travel from the mouth of the river to Manaus on large, mainstream cruise ships. Along the way, they offer shore excursions into the tributaries. There are also a number of smaller riverboat cruises up the River Negro from Manaus.

Smaller river cruises ply the Amazon in Peru, exploring the Pacaya Samiria National Reserve. Iquitos, 600 miles northeast of Lima (a 90-minute flight), is the central city for the Peruvian rainforest. (For more on both stretches, read Amazon River Cruise Basics).

The sheer breadth of the river can be the allure in Brazil, especially for those who favor large cruise ships. However, the 1,000-mile stretch of the Amazon from its mouth to Manaus is a heavily populated commercial waterway with many other vessels and a number of sizable ports. Its width can range from one to six miles during low water season, and rise to 30 miles in wet season.

Peru has the advantage of many narrower rivers where one can get up close with the birds, mammals and plants in the rich preserves. In fact, on the tranquil Peruvian riverboats — quite small compared to the cruise ships — you are actually in the rainforest for four to 10 days. Also, it’s possible to combine the trip with time in Machu Picchu, the Sacred Valley, Lake Titicaca and Cuzco, as they are a short hop by air.

In both countries, you’ll find excursions that help you make the most of your front seat to rainforest flora and fauna.