Operation Crossroads was a pair of nuclear weapon tests conducted by the United States at Bikini Atoll in mid-1946. They were the first nuclear weapon tests since Trinity on July 16, 1945, and the first detonations of nuclear devices since the atomic bombing of Nagasaki on August 9, 1945. The purpose of the tests was to investigate the effect of nuclear weapons on warships.
Prospective Operation Crossroads target ships and support ships at Pearl Harbor on February 27, 1946. Ships from front to rear: USS Crittenden, Catron, Bracken, Burleson, Gilliam, Fallon, unknown ship, Fillmore, Kochab, Luna, and an unidentified tanker and Liberty ship. On the right are LSM-203 and LSM-465. Farther in the background are a floating drydock and a merchant ship hulk.
Nevada painted in high visibility orange for the atomic tests
The target fleet after test Able. The aircraft carrier Saratoga is right-center with Independence burning at left-center. The ex-Japanese battleship Nagato is between them. The ship at left, next to the battleship Pennsylvania, is trying to wash down the radioactivity with water from the lagoon.
Aerial view of the Able mushroom cloud rising from the lagoon with the Bikini Island visible in the background. The cloud carried the radioactive contaminants into the stratosphere.
Nuclear weapons of the United States
The United States was the first country to manufacture nuclear weapons and is the only country to have used them in combat, with the bombings of Hiroshima and Nagasaki in World War II. Before and during the Cold War, it conducted 1,054 nuclear tests, and tested many long-range nuclear weapons delivery systems.
The Trinity test of the Manhattan Project was the first detonation of a nuclear weapon.
Protest in Bonn against the deployment of Pershing II missiles in West Germany, 1981
The U.S. conducted hundreds of nuclear tests at the Nevada Test Site.
Members of Nevada Desert Experience hold a prayer vigil during the Easter period of 1982 at the entrance to the Nevada Test Site.