The Colorado River runs about 1,450 miles from the Rocky Mountains of Colorado through the Grand Canyon, past Lake Mead and into Mexico. Its name comes from the Spanish word for reddish, a reference to the heavy silt it carries. Dams, reservoirs and aqueducts divert almost its entire flow for farms and cities, supplying water to around 40 million people. Water use has dried up the lower 100 miles of the river, which has rarely reached the Gulf of California since the 1960s. Since 2000, drought has increased pressure on supplies that are already fully allocated among states and countries.

Hampi is a UNESCO World Heritage Site in Karnataka, India, with more than 1,600 surviving remains spread over 4,100 hectares. It was the capital of the Vijayanagara Empire from 1336 to 1565. Travellers from Persia and Portugal described it as a prosperous, wealthy and grand city with temples, markets and farms along the Tungabhadra River. By 1500 it was estimated to be the world's second-largest city after Beijing, and probably India's richest at the time. In 1565 a coalition of Muslim sultanates defeated the Vijayanagara Empire, its capital was conquered and destroyed, and the city was left in ruins. Hampi remains a religious centre, with the active Virupaksha Temple at its heart.