And many have been found only recently. At Sipan, on the far north coast, the richest tomb complex in the Western Hemisphere wasn't discovered until 1987. Assisted by Chicago's Field Museum and researchers from Northern Illinois University, excavation has just begun on Caral, the oldest city in the Americas, whose construction in 2,600 BC coincides with that of Egypt's Great Pyramid at Khufu. Nestled on the crest of a 9,900-foot mountain between two vast tributaries of the Amazon in western Peru, the great stone fortress of Kuelap slumbered for centuries beneath a covering of bromeliads and orchids. Today it's possible to reach the circular redoubt, whose entrance is so narrow that only one person can pass through at a time, and discover a hidden city of 400 buildings with sculpted friezes and elaborately carved cornices.
It is almost 10 p.m. when we land in Iquitos and walk into a wall of humidity as thick as the jungle nibbling at the airport tarmac. It seems we've arrived at the end of the road, except there are no roads linking Iquitos, an Amazonian river city of more than 360,000, with the outside world. Located literally in the middle of a trackless rain forest, Iquitos wakes up late, chases lunch with a siesta, and parties deep into the night. Indeed, by 11 p.m., when we finally reach the hotel through a gauntlet of careening motorcycles with sidecars, I think we've fallen into a wormhole and landed in Reno, Nevada.