Early in the morning of May 5, 1955, millions of Americans viewed the aweinspiring spectacle of a nuclear blast, Operation Cue, the join test pooject of FCDA, AEC, and private industry at the Atomic Energy Commission's Nevada Test Site. The purpose of Operation Cue was dual: to give the American public some conceptin of the tremendous destructive energy of an atomic explosion and to test materials and techniques necessary to divil defense preparedness. In additon to the FCDA and AEC test staff, more than 200 civil defense personnel from State and local organizations participated. State and local observers helf field exercises in the exposed area when it was safe to enter, carrying out rescue, medical, warden, police, mass feeding, and other civil defense functions. As part of the exercise a selected group of civil defensee personnel experienced the blast in a trench 2 miles from ground zero. Test homes and commercial buildings showing representative types of construction, communications and utilities installations, and shelters were built at different ranges from ground zero. Experts were able to observe the technical effects of an atomic detonation on the test items, and the public was given a general idea of the destructive power of the weapon. Vehicles, food, clothing materials, and other items exposed in the test represented hundreds of thousands of dollars in time and materials donated by private