Oct 2 2011
During the 1950's United States conducted many nuclear tests over the "Pacific Proving Grounds". This was one of them. In 1958 operation "Cactus" was completed - an 18 kT (kiloton) nuclear bomb was dropped and this 350ft crater was created.
The explosion codenamed "Cactus".
In the late 1970's the United States Government began cleaning up the radioactive debris left by these blasts and decided to deposit them in the created crater left by the explosion. The end result was a vault that cost the government nearly a quarter of billion dollars.
The result: an enormous, foot-and-a-half-thick, 100,000-square-foot dome consisting of 358 gigantic concrete panels.
The crater beside the dome is another nuclear test done by the US Government.