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The airport code for Enewetak Auxiliary Airfield is ENT.
1952 Enewetak in the Pacific.
Part of the Marshall Islands are a part of the US. (The islands of Bikini and Enewetak use to be US nuclear test sites.)
No.
However the first US hydrogen bomb test Ivy Mikecompletely destroyed an island (Eugelab in Enewetak Atoll), turning it into a crater.
The US exploded the first one in the Enewetak atoll in the pacific. The second one was exploded by Russia somewhere in the old USSR.