The beating heart of the Brazilian rainforest. This bustling frontier town emanates a verdigris grandeur, a throwback to the rubber boom gone by, illustrated best by the Belle Epoque opera house, with its marble halls and 198 Murano glass chandeliers. Drift away to the Philharmonic strains of Verdi or Mozart under frescoed ceilings in the midst of the steamy jungle. Outside, the inky Rio Negro meets but doesn’t merge with the more muddied Rio Solimoes, and pink dolphins, manatees and river otters ply the wide and winding waterways, the banks and jungle trails scattered with waterfalls, wild orchids, spider monkeys and jaguars.