Iquitos is bustling, heterogeneous, grubby, rakish. In short, interesting. Since there are no roads that lead anywhere (with the single exception of a 70 mile-long road that took 30 years to build and connects the town of Nauta, population15,000, to Iquitos), nearly everyone gets around by motocarro, a kind of covered rickshaw propelled by motorcycle, the engines of which provide a constant background roar. Iquitos is growing wildly, already having over a population of over 600,000, fed by people from the jungle lured by possibilities of having different or better lives. All of our guides - Cesar, Daniel, Victor, Roland - had been born in remote parts of the jungle and still have family there. Victor's father, for example, who lives a day's boat trip away down the Pacaya River, still catches fish with a spear. Near where Victor's family lives but further away from the river (where one still finds ''traditional'' tribes) lives a group known as ''cat people'' because of sticks thrust through their noses that look like whiskers. The way Iquitos is developing, its size could one day rival Manaus, the famously huge Brazilian frontier town in the heart of Amazonia. But no matter how large Iquitos gets it's likely to remain a city of two- or at most three-story buildings. A couple of years ago some shortsighted person built a ten-story building that almost immediately started to lean as it settled into Iquitos' soft sedimentary clay. Instead of taking it down, the government bought it and popped several antennas on top, and it remains a decaying fungus-spotted blue eyesore.