National Guardsmen are put through riot training in Boston's Commonwealth Armory on Friday, October 18, 1974. Massachusetts Gov. Francis W. Sargent called up the guard to quell school violence, but the city has been relatively calm and the guard has remained in the armories. (Photo by JWG/AP Photo)

Kenichi Ito runs on his arms and legs on a race course on his way to setting the Guinness World Record fastest time for the 100-meter dash on all fours at Komazawa Olympic Park Stadium in Tokyo Thursday, November 14, 2013. The 30-year-old Japanese finished in 16.87 seconds Thursday, shaving more than half a second off his 2012 run of 17.47. (Photo by Shizuo Kambayashi/AP Photo)

Young female Ibex on the fork of Disteis (2,200 m), near the top of the Jof di Montasio (Friuli, Italy). (Photo by Stefano Zocca)

“The last known individual of the subspecies was a male named Lonesome George (Spanish: El Solitario Jorge/George), who died on 24 June 2012. In his last years, he was known as the rarest creature in the world. George served as a potent symbol for conservation efforts in the Galápagos and internationally”. – Wikipedia. (Photo by Rodrigo Buendia/AFP)

American soldiers leaping from an armoured personnel carrier during exercises in Korea, 17th March 1954. (Photo by Three Lions)

Waves crash over lava as it flows into the ocean near Volcanoes National Park in Kalapana, Hawaii on November 27, 2012. A volcano on Hawaii's largest island is spilling lava into the ocean, creating a rare and spectacular fusion of steam and waves that officials said on Tuesday could attract thrill seeking visitors if it continues. (Photo by Hugh Gentry/Reuters)

Zoee Heath of New South Wales competes in the womens U18 discus throw during day two of the Australian Junior Athletics Championships at Sydney Olympic Park Athletic Centre on March 11, 2011 in Sydney, Australia.

Children in Hiroshima, Japan, wearing masks to combat the odour of death after the city was destroyed by the first atom bomb. (Photo by Keystone/Getty Images). 1945