Manaus is also the gateway for many visitors to the Amazon. Be sure to experience this extraordinary city before you head off to the rainforest.
The citizens of Manaus became some of the wealthiest in the world during the rubber boom of the late nineteenth century, when many luxurious public and private buildings were built.
Chief among these is the iconic opera house, the Teatro Amazonas, built in 1896 and modelled on the Grand Opera de Paris. It is lavishly decorated with Venetian lights and masks, Murano crystal, Italian marble floors and much besides, to flaunt the wealth of the era that created it - a time when the streets were lit by the world's first electric street lighting, champagne flowed like water, horses drank vintage claret, and high society in Manaus would send their laundry to Paris.
The municipal market, the Mercado Adolfo Lisboa, is a replica of the former market buildings of Les Halles in Paris - all fin de siecle wrought ironwork (reputedly designed by Eiffel) and shipped out from Europe. It is still in full use and bursting with Indian crafts, tropical fruit and vegetables, fish, religious trinkets and other local items, from the prosaic to the exotic.
You should also make a point of visiting the 'rubber museum', the Centro Cultural Palacio Rio Negro, housed in the former mansion of a German rubber merchant.
The Museu de Indio, a dusty affair run by Salesian missionaries, contains a fine collection of ceramics, sacred masks and replicas of Indian dwellings.
Most street corners in the centre of Manuas have stalls selling different fruits and juices made from local fruits native to the Amazon region, such as cupuaçu and taperaba. A great favourite is guarana, derived from an Amazonian berry and now an extremely popular energy drink all over Brazil.
Local cuisine is based around fish such as jaraqui, tucupi, tucuma and pupunha which, despite their fearsome appearance, are generally delicious.
Today the grand buildings from the rubber boom stand next to modern, towering skyscrapers and sprawling suburbs, in stark contrast to the rainforests that surround Manaus on every side.
Manaus sits at the confluence of the Amazon with its largest tributary, the Rio Negro. (In fact Brazilians only call it the Amazon from this point - upstream it is the Rio Solimões.) The waters of the Rio Negro drain the Guyana Shield - ancient rocks from the precambrian era whose nutrients have long been washed away. Unlike the Solimoes whose milky brown waters carry a heavy load of sediments eroded from the Andes, the waters of the Rio Negro are clear, but stained the colour of black tea by tannins leached from forest leaves. A popular river excursion to the 'Meeting of the Waters' visits the place where they converge, running side by side without mixing for several kilometres.
You might think that Manaus, being at the heart of the rainforest, would be sensitive to the Amazon's global importance for the planet's welfare. If so, you would be largely disappointed. The city's zoo sums up attitudes to the natural world that date back decades, and some of the supposed 'eco' experiences around the city are generally little better and sometimes worse. You will need to go beyond Manaus to experience the Amazon sustainably and in its natural state.