'Shouting "Geronimo" while jumping has its origins in the U.S. Army. '
Geronimo was a fearless and ruthless military leader of the Chiricahua Apache, the last tribe to surrender to the U.S. in the 1880s. His given name was Goyahkla; Mexican troops, astonished by his bravery, dubbed him Geronimo after Saint Jerome. In 1940, the U.S. 501st Parachute Infantry Regiment assumed Geronimo for their motto and logo, and after watching the 1939 film Geronimo, one especially nervous member of the regiment said he would shout the leader's name as they performed a tricky jump to show he wasn't scared, giving birth to the curious tradition.