image

Operation Crossroads atom bomb test. Mushroom cloud rising from the Baker underwater atomic explosion carried out at Bikini Atoll, in the Pacific, on 25th July 1946. This was the first underwater atom bomb test. It was detonated 27 metres below the surface and had a yield of 21,000 tons of TNT. The column of water vapour reached thousands of metres into the air, and a wave of water overwhelmed the unmanned ships (lower frame). This was the second and last atom bomb test in the Operation Crossroads series. (KEYSTONE/SCIENCE PHOTO LIBRARY/US NATIONAL ARCHIVES AND RECORDS ADMINISTRATION/ SCIENCE PHOTO LIBRARY)