North Korea claims to have detonated its first hydrogen bomb, but international experts doubt it.
Video of bomb test in Alaska
Amchitka, one of a string of the Aleutian Islands in the southwest region of Alaska was selected by the US Atomic Energy Commission to be the site for 3 underground detonations of nuclear weapons. The tests were: Long Shot, an 80-kiloton blast in 1965 Milrow, a 1-megaton blast in 1969 and Cannikin in 1971, at 5 Mt, was the largest underground test ever conducted by the United States. The tests were highly controversial, with environmental groups fearing that the Cannikin explosion, in particular, would cause severe earthquakes and tsunamis.