The capital of the state of Amazonas, the city of Manaus had a monopoly on the rubber industry in the late 1800s and was known for its extravagant lifestyles. Jewel-encrusted silverware, gold-adorned balconies, private zoos and an opera house that cost the public 10 million dollars represented the immense wealth of the population. Although rubber trees are still plentiful in the neighboring Amazon rainforest, natural rubber has been largely replaced in industry by synthetic products and the city has lost much of its luster. Still, Manaus remains the gateway to the Amazon, and there are several different options for viewing the largest rainforest on earth.