Holding the title of world’s largest rainforest is no idle claim. The Amazon is nothing less than immense (it takes up 60 percent of all of the territory in Brazil alone!) and distances are enormous. Additionally, there are very few roads. Those that exist tend to be in precarious shape, which leaves you dependent on riverboats or airplanes for most of your transportation.

Unless you’re a jungle junkie or a river rat, the best and most efficient way to explore the Amazon is to base yourself in either Manaus or Belém—or else to split your time between the two. Three days in each city is a minimum since each is a fascinating destination in its own right (although Belém offers more historical and cultural attractions than Manaus, which is more modern and less attractive). From both you can venture forth into the surrounding area, in accordance with how much time you have at your disposal.

From Belém, set aside 3–4 days for a trip to Ilha de Marajó, or to the beaches on Ilha do Mosqueiro or Ilha de Algodoal. From Manaus, you can spend a day or two in nearby Presidente Figueiredo, with its dozens of waterfalls, or 2–3 days in jungle lodges within a short distance of the city.

To really get a feel for the jungle, you should definitely set aside a minimum of 4–5 days, which could be spent on an organized excursion up the Rio Negro or Rio Solimões or at a far-flung jungle lodge in an area such as the Mamirauá Reserve or the Anavilhanas archipelago.

If neither time nor comfort is a major issue, the classic Amazonian trip is a boat ride from Manaus to Belém, or vice-versa, which will set you back 5–6 days, the price of a hammock (or a cabin), and a lot of bug repellent. On the way, you can stop at Santarém, whose surrounding attractions (most notably the beaches of Alter do Chão) deserve at least three days.

If you’re pressed for time and don’t want to miss Santarém, you can easily fly there from both Belém and Manaus. In general, despite the cost, flying between far-flung Amazonian destinations saves you an awful lot of time that could be spent on more varied and diverting activities than sitting on a crowded boat in the middle of the river.

The Amazon is always fairly wet, humid, and hot, as in temperatures of 35–40°C (95–104°F) and humidity levels of 80 percent. Belém is one of the rainiest cities on the planet. December to June is considered the wet season, and July to November is considered slightly less wet. The good thing about Belém’s rains is that they are torrential, but they pass. Belenenses have dealing with the daily downpours down to a fine art. They’re able to predict when a storm is coming—and blowing over—quite well. Manaus and the Amazonian Basin possess a more pronounced dry season, which lasts roughly from July to November and sees somewhat cooler temperatures (23–30°C, 73–86°F).

If you plan on traveling into the jungle, the season you choose will have a significant impact on your trip due to the vast flooding of the Amazon and its tributaries. During the dry season, the water recedes, leaving beaches exposed and forest floors dry and hikable. Fishing is also better at this time. However, the wet season’s high waters give you access (by boat) to temporarily flooded forests known as igapós, where you’ll see more wildlife.

Although it’s always hot during the day, nights in the forest can be cooler, so it’s always a good idea to have long pants and a light jacket or sweater. A light blanket is recommended if you’re going to be on a riverboat. As for Santarém, it receives less rain than either Belém or Manaus—the better with which to soak up sun on its lovely beaches.

Regardless of when you visit, a vaccine for yellow fever is necessary (proof is required). You can get these shots for free at public health clinics throughout Brazil, but you’ll need to have the injection 10 days prior to entering the Amazon. Some tropical disease experts also recommend taking antimalarial pills, even though they’re not always effective and can have strong side effects. As a precaution, bring lots of mosquito repellent and wear long sleeves, especially around the sunrise and sunset hours when mosquitos are on the prowl. Most accommodations offer mosquito netting.