Quito, Ecuador, is a place of truly dramatic beauty in a high Andean valley. With its rapidly expanding population, the capital city of Ecuador is bustling and alive and experiences the usual problems of a very large city. Quito is a major business center and, since its Colonial center was declared as one of the first UNESCO World Heritage sites in 1978, it is also a prime tourist destination. However, many of its three million residents live in barrios with little infrastructure, and many of these crowded, rather poor communities are scattered across the eastern slopes of Guagua Pinchincha volcano.

Quito owes its very site to volcanoes: the urban center is located on a bench composed of older pyroclastic flow deposits and interbedded sediments. The city has grown into a 25-mile-long sprawl that spills out into the north–south Inter-Andean Valley; it is bounded on the west by a line of volcanoes and on the east by older volcanoes and the Chillos Valley. Greater Quito has been exposed throughout its history to volcanic hazards, including ash falls from the nearby Guagua Pichincha volcano and mudflows from Cotopaxi volcano, located 37 miles to the south.