The world's first nuclear explosion occurred on July 16, 1945, when a plutonium implosion device was tested at a site located 210 miles south of Los Alamos, New Mexico, on the barren plains of the Alamogordo Bombing Range, known as the Jornada del Muerto. Inspired by the poetry of John Donne, J. Robert Oppenheimer code-named the test "Trinity." Hoisted atop a 100-foot tower, the plutonium device, or "Gadget," detonated at precisely 5:30 a.m. over the New Mexico desert, releasing 18.6 kilotons of power, instantly vaporizing the tower and turning the surrounding asphalt and sand into green glass. Seconds after the explosion came an enormous blast, sending searing heat across the desert and knocking observers to the ground. The success of the Trinity test meant that an atomic bomb using plutonium could be readied for use by the U.S. military.
The Trinity site is now part of the White Sands Missile Range and is owned by the U.S. Department of Defense (DOD). Ground zero is marked by an obelisk made of black lava rock, with an attached commemorative sign. A slightly depressed area several hundred yards across surrounds the monument, indicating where the blast scoured the ground. Only a few pieces of the green glass, trinitite, remain in a protected enclosure. Outside the fenced-in ground zero area lies "Jumbo," the 214-ton steel container built to contain the plutonium if the 5,300 pounds of high explosives in the bomb detonated but no nuclear explosion resulted. Ultimately, Jumbo was not used. The restored McDonald ranch house, where the device's plutonium core was assembled, is located about two miles to the south. The remnants of the base camp where some 200 scientists, soldiers, and technicians took up temporary residence during the summer of 1945 is about ten miles southwest of ground zero. Remnants of the observation points 10,000 yards out are also still visible. The Trinity site is currently opened to the public by the National Park Service twice a year. Tours are given by DOD on request.