Yucca Flat, Nev.
Scientists set off a thermonuclear weapon at a test site here Thursday.
The blast was about seven times as powerful as the atomic bombs dropped on Japan. The desert above ground-zero collapsed 21 minutes after the detonation. The diameter of the subsidence was large enough to hold the Empire State Building. A spokesman for the Department of Energy said that the test was a success and that no radiation was released into the atmosphere.