Cruising the Amazon is an expensive business: the shortest trips can cost over US$1000. It’s a popular pastime, too, and advance reservations are often necessary (and often mean discounts). Cruises naturally focus on the Río Amazonas, both downriver (northeast) toward the Brazil–Colombia border and upriver to Nauta, where the Ríos Marañón and Ucayali converge. Beyond Nauta, trips continue up these two rivers to the Reserva Nacional Pacaya-Samiria. Trips can also be arranged on the three rivers surrounding Iquitos: the Itaya, the Amazonas and the Nanay. Operators quote prices in US dollars. A useful booking website is www.amazoncruise.net.