South Korean military soldiers take part in the South Korea and U.S. joint military exercise to commemorate the 63th Korea Armed Forces Day at the Seungjin firing drill ground on September 30, 2011 in Pocheon, South Korea. The exercise is intended to prepare the South Korean defence force for any potential action from North Korea. (Photo by Chung Sung-Jun/Getty Images)

A lighting bolt flashes in the sky as U.S. Army M1A1 Abram tanks roll through the desert December 9, 2002 near the Iraqi border in Kuwait. (Photo by Joe Raedle/Getty Images)

Two dummy tanks being pushed along a road by German soldiers. (Photo by Hulton Archive/Getty Images). Circa 1925

A Mark IV tank, part of the parade at the Lord Mayor's Show in London. (Photo by Topical Press Agency/Getty Images). November 1917