Keywords: NTS - Windowless Modular Structure - before.jpg Nevada Test Site Frenchman Flat <br /> This brick masonry structure shelter was built for the June 24 1957 Priscilla test The walls of the 32-foot by 28-foot building consist of two layers of brick with reinforcing steel in the center forming a thickness of 10 inches The flat roof is reinforced concrete The blast from the nuclear test displaced the wall facing ground zero east side about one-quarter of an inch <br /><br /> Photograph taken before the test 564 PLU-57-184 Federal Government of the United States PD-USGov Plumbbob Priscilla Flat roofs |