This spiked helmet, known as a pickelhaube, was originally designed by King Frederick Wilhelm IV of Prussia in 1842. This helmet design was popular among the Russian and German militaries and police prior to and during World War I. Capt. Edward V. Rickenbacker, America’s highest scoring ace of WWI, brought this Prussian cavalry officer’s helmet home as a wartime souvenir. It is unknown how he attained it. (U.S. Air Force photo)