At 5:29 a.m. on July 16, 1945, the United States detonated the first nuclear weapon in a remote stretch of the Jornada del Muerto desert in New Mexico, about 35 miles southeast of Socorro. The test was part of the Manhattan Project, and the device was a plutonium implosion bomb, the same design later dropped on Nagasaki. Its explosive yield was about 25 kilotons of TNT, and it left a large cloud of fallout. Scientists had doubts about the complex design, which is why the test was needed in the first place. Oppenheimer named the test Trinity, possibly after a poem by John Donne. About 425 people were present, including Enrico Fermi, Richard Feynman, Edward Teller and John von Neumann. Nearby residents were not evacuated, a decision that later postwar radiation guidelines, partly based on Trinity data, would have ruled out at those distances.

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.