At the end of WWII the US began to look at the potential and impact of nuclear weapons in numerous tests. One of the earliest was "Operation Crossroads" which was a series of two blasts set off in the Bikini Atoll in the Marshall islands which was intended to look at the vulnerability of the US fleet. It was the first tests initiated after the bombs at Hiroshima and Nagasaki. The first test was to detonate a bomb at 520 feet above sea level, in the midst of a stationary fleet, and the second was a blast 90 feet underwater. As you could imagine the results were catastrophic to the test fleet, as well as the surrounding islands. This map shows the span of the South Pacific, once the island to island battle ground, and here a red overprint simply shows "Scene of Operation Crossroads (Atomic bomb experiment in Central Pacific)". The post script to this series of tests was that the area is still radioactive, and is a visiting spot for divers. Not a common map to find.
Condition is very good. Image size is approximately 18 x 26 (inches)