Upshot-Knothole Grable, a test carried out by the U.S. military in Nevada on May 25, 1953. A 280mm nuclear shell was fired 10km into the desert by the M65 Atomic Cannon, detonating in the air, about 500 feet above the ground, with a resulting 15 kiloton explosion. (U.S. Department of Defense)

Exposed wiring of The Gadget, the nuclear device which exploded as part of Trinity, the first nuclear weapons test of an atomic bomb. At the time of this photo, the device was being prepared for its detonation, which took place on July 16, 1945. (U.S. Department of Defense)

Los Alamos director J. Robert Oppenheimer is seen in silhouette as he oversees final assembly of The Gadget at the Trinity test site in July of 1945.

The expanding fireball and shockwave of the Trinity explosion, seen .025 seconds after detonation on July 16, 1945. (U.S. Department of Defense)

A longer-exposure photograph of the Trinity explosion seconds after detonation on July 16, 1945. (U.S. Department of Defense)

A fireball begins to rise, and the world's first atomic mushroom cloud begins to form, nine seconds after Trinity detonated on July 16, 1945. (U.S. Department of Defense)

A massive column of water rises from the sea as the U.S. detonate an atom bomb at Bikini Atoll in the Pacific in the first underwater test of the device, July 25, 1946. (AP Photo)

A huge mushroom cloud rises above Bikini atoll in the Marshall Islands on July 25, 1946 following an atomic test blast, part of the U.S. military's Operation Crossroads. The dark spots in foreground are ships that were placed near the blast site to test what an atom bomb would do to a fleet of warships. (AP Photo)

On November 16, 1952, a B-36H bomber dropped a nuclear bomb over a point north of Runit Island in the Enewetak atoll, resulting in a 500 kiloton explosion -- part of a test code-named Ivy.

Operation Greenhouse took place in the spring of 1951, consisting of four explosions at the Pacific Proving Grounds in the Pacific Ocean. This photo is from the third test, George, on May 9, 1951, the first thermonuclear bomb test, yielding 225 kilotons. (U.S. Department of Defense)

"Rope tricks" are seen in this image of a nuclear explosion taken less than one millisecond after detonation. During operation Tumbler-Snapper in 1952, this nuclear test device was suspended 300 feet above the Nevada desert floor, and anchored by mooring cables. As the ball of plasma expanded, the radiating energy superheated and vaporized the cables just ahead of the fireball, resulting in the "spike" effects. (U.S. Department of Defense)

During Plumbbob test at the Nevada Test Site on August 30, 1957, the Franklin Prime shot is detonated from a balloon in Yucca Flat at an altitude of 750 feet.

The test explosion of a hydrogen bomb during Operation Redwing over the Bikini Atoll on May 20, 1956

Ionization glow surrounds the cooling fireball of the Diablo shot, fired in Yucca Flat at 4:30 a.m. Monday, July 15, 1957. (National Nuclear Security Administration / Nevada Site Office)

The flash of the exploding nuclear warhead of an air-to-air rocket is shown as a bright sun in the eastern sky at 7:30 a.m. July 19, 1957 at Indian Springs Air Force Base, some 30 miles away from the point of detonation. A Scorpion, sister ship of the launching aircraft, is in the foreground. (National Nuclear Security Administration / Nevada Site

The fireball of the Priscilla shot, fired on June 24, 1957, as a part of the Operation Plumbbob series. (National Nuclear Security Administration / Nevada Site Office)

NATO observers watch the detonation of Operation Plumbbob Boltzmann on May 28, 1957. (National Nuclear Security Administration / Nevada Site Office)

The tail section of a U.S. Navy Blimp is shown with the Stokes cloud in background at the Nevada test Site on August 7, 1957. The blimp was in temporary free flight in excess of five miles from ground zero when it was collapsed by the shock wave from the blast. The airship was unmanned and was used in a military effects experiment. (National Nuclear Security Administration / Nevada Site Office)

Observers view atmospheric testing during operation Hardtack I -- a thermonuclear detonation during the Pacific tests in 1958. (National Nuclear Security Administration / Nevada Site Office)

A view of the Arkansas test, part of Operation Dominic, a series of over 100 nuclear test explosions in Nevada and the Pacific in 1962. (U.S. Department of Defense)

The rising fireball of the Aztec test, part of Operation Dominic, a series of over 100 nuclear test explosions in Nevada and the Pacific in 1962. (U.S. Department of Defense)

Shot during Fishbowl Bluegill, this is an image of an explosion of a 400 kiloton nuclear bomb taking place in the atmosphere, 30 miles above the Pacific, as viewed from above, in October 1962. (U.S. Department of Defense)

Expanding rings surround a mushroom cloud, during the Yeso test explosion, part of Operation Dominic, a series of over 100 nuclear test explosions in Nevada and the Pacific in 1962. (U.S. Department of Defense)

Sedan Crater was formed when a 100 kiloton explosive buried under 635 feet of desert alluvium was fired at the NTS on July 6, 1962, displacing 12 million tons of earth. The crater is 320 feet deep and 1,280 feet in diameter. (National Nuclear Security Administration / Nevada Site Office

A 1971 photo of a nuclear bomb detonated by the French government at the Mururoa atoll, French Polynesia. (AP Photo)

A photo of a nuclear bomb detonated by the French government at the Mururoa atoll, French Polynesia. Original here. (Pierre J. / CC BY NC SA)