On May 27, 1957, 5 miles south of the Albuquerque airport, a Mark 17 H-bomb (pictured at left) was accidentally dropped from a B-36 Peacemaker on it’s way to Kirtland AFB. The plutonium pit was not on board, but the fissile ‘spark plug’ detonated. Bits of the bomb, the biggest ever deployed by the US at 15-20 megatons, could still be found in the area (see picture below). But the authors of this 2010 report urged the collecting public to hurry, as the area would soon be covered over by a development called “Mesa del Sol”. And so it now is.(source: Carl Willis, “Albuquerque, Ground Zero”)