The Amazon River in South America is the second longest river in the world. The Ucayali-Apurímac river system is thought to be its main source and it flows through Guyana, Ecuador, Venezuela, Bolivia, Brazil, Colombia and Peru on its path from the Andes to the sea. It has over 1,100 tributaries, 17 of which are over 1,500 km (930 mi) long. Its width varies between 1.6 and 10 km (1.0 and 6.2 mi) at low stage, but in the wet season expands to 48 km (30 mi) or more.
Over a one-third of all species existing in the world live in the river and surrounding rainforest, In terms of biodiversity, it is the richest tropical forest in the world. Over 2,100 kinds of fish are currently recognized in the Amazon Basin, and more are constantly discovered. The river also hosts the orinoco whale, the boto river dolphin, the tucuxi river dolphin, the Amazonian Manatee, and the giant otter, the biggest of its kind. Anacondas swim in the shallow waters, alongside crabs, algae, turtles and the caiman.
A popular base to experience the Amazon is the Brazilian city of Manaus. It sits near many eco-lodges as well as the "Meeting of the Waters." The muddy waters of the Rio Negro collide with the lighter shades of the Rio Solimões, travelling alongside one another for a stretch before amalgamating into one uniform colour. The recommended time to see wildlife on boat tours is during the rainy season, January to May.
There are a host of activities in and around the Amazon, but the best way to experience it is via a river cruise. Cruises tend to last several nights, and can include kayaking, tree canopy zip lines, wildlife viewing and trekking.
Vaccinations for malaria, dengue, hepatitis and yellow fever are recommended several months before the trip. Travelers should avoid drinking tap water or eating raw foods. Take rainproof clothing, sun cream and insect repellant.