1951 - Enewetok Atoll
The Greenhouse Test Series was conducted at Enewetok Atoll in April and May of 1951. It consisted of four relatively high yield tests (by the standards of the time) - Dog, Easy , George, and Item. Dog and Easy were proof tests of two new strategic bombs the Mk 6 and Mk 5 respectively. George and Item were the first true tests of thermonuclear fusion - the release of fusion energy from thermally excited nuclei. George was a research experiment that studied deuterium-fusion burning when heated by thermal radiation. Item was the first test of the principle of fusion boosting of fission devices.