Sandia Base personnel were dispatched to assist in two major incidents involving the loss and recovery of nuclear weapons in the 1960s. In 1966, a Boeing B-52 Stratofortress bomber and a Boeing KC-135 Stratotanker air refueling plane collided in mid-air over the Mediterranean Sea off the coast of Spain. This event is referred to as the Palomares incident. Three of four missing nuclear weapons were found on land near the fishing village of Palomares in Spain. The fourth was found in the sea after a lengthy search. The second incident occurred in 1968 when a B-52 bomber crashed near Thule, Greenland. Three weapons were recovered; a fourth is believed to remain in the ocean.