2,836km (1,762 miles) NW of Rio de Janeiro, 2,682km (1,666 miles) NW of São Paulo

On the surface, Manaus looks a lot like other Brazilian cities. The old downtown is shabby and bustling. Along the shoreline in the upscale Ponta Negra area you'll find the familiar beachside high-rises, wide streets, and waterfront kiosks. But stop for a moment and contemplate: You're in the middle of nowhere with 1,610km (1,000 miles) of forest in every direction.

Inhabitants of the largest city in the Amazon, Manaus's 1.6 million people live on the shores of the Rio Negro, just upstream from where it joins the Rio Solimões to become the Amazon. Though first settled in the 1600s, there's a frontier feel to the place.

Near the end of the 19th century, when the Amazon was the world's only rubber supplier, there was a 30-year boom in rubber and Manaus got rich indeed. Some of the city's finest buildings date back to this time, among them the Customs house and the famous Teatro Amazonas. The boom ended around 1910, some years after an enterprising Brit stole some Amazon rubber seeds and planted them in new plantations in Malaya (modern-day Malaysia).

The city's next boom came in 1966, when Manaus was declared a free-trade zone. Electronics assembly plants sprouted across the city, and workers poured in to staff the factories. In the space of just a few years the city's population doubled to half a million. The retail traffic dried up in the early '90s when the government reduced import tariffs, but with the free-trade zone still in place, manufacturing carries on.

These days, the city's biggest employer is the Brazilian army, which has jungle-training schools, listening stations, and a substantial standing force stationed in the city -- all to preserve Brazilian sovereignty over the Amazon. Tourism has also expanded, most of it focused on the rainforest. Manaus is the main departure point for trips into the Amazon.