Amazonas, Brazil’s largest state, is the beating heart of the world’s biggest rainforest. Its gateway is Manaus, where the opulent Teatro Amazonas recalls the rubber-boom era and, just outside the city, the dark Rio Negro and the sandy Solimões run side by side for miles in the famous Meeting of the Waters. From there, river cruises and jungle lodges lead deep into the forest to spot pink river dolphins, sloths and giant water lilies, and to meet riverside communities. Don’t leave without tasting tambaqui grilled over coals and tacacá, a tangy broth of tucupi and jambu. For Americans dreaming of the Amazon, this is where the adventure begins.