The United States conducted an atmospheric nuclear test for the last time, and all of its tests since then have been made underground.

The last atmospheric test ever would be by China on October 16, 1980.

Of these atmospheric tests, 330 were conducted by the United States.

It would also be the last atmospheric nuclear test conducted by the United States.

So starting on Feb. 5, 1952, the national press was invited in and allowed to cover an atmospheric test.

Other than a few atmospheric tests in the 1950's, the B-52 never had to perform its principal job: deliver a nuclear weapon.

A total of 41 atmospheric nuclear tests were conducted at Mururoa between 1966 and 1974.

It is the fallout of atmospheric tests which ended in 1974.

Five atmospheric nuclear tests of small power (10-40 kt) were performed over the site in 1957-1961.

The Soviet Union is believed to have made 137 atmospheric tests.