Irina, worker of a petrol station, now member of reconnaissance team of pro-Russian rebels' in the town of Makievka, eastern Ukraine, October 6, 2014. Like the men in the conflict, the women come from all walks of life. Some women come to serve with their husbands and boyfriends, others are single. Female fighters on both sides said the men in their units treat them as equals, though sometimes showing more leniency. They have little respect for men who have not taken up arms. On both sides the fighters expect a long conflict, despite the fragile ceasefire now in place. (Photo by Shamil Zhumatov/Reuters)

Ngorongoro Crater (Tanzania). At 610m deep and 260 sq km, this is the largest unflooded caldera in the world. A blue-green vision from above it's a haven for engangered wildlife and Maasai livestock. The crater was formed three million years ago when a giant volcano, which could have been as high as Kilimanjaro, exploded and collapsed. The caldera formed the concentric fractures in the crust cracked down to a magma reservoir deep underground. (Photo by John Bryant/Getty Images)

U.S. Army helicopters providing support for U.S. ground troops fly into a staging area fifty miles northeast of Saigon, Vietnam, August 28, 1966. Helicopter fuel is stored in the large rubber tanks, foreground. (Photo by Henri Huet/AP Photo)

U.S Army combat camera photographer Spc. Hilda Clayton took this photo July 2, 2013 that was released by the U.S. Army, that shows an Afghan soldier engulfed in flame as a mortar tube explodes during an Afghan National Army live-fire training exercise in Laghman Province, Afghanistan. The accident killed Clayton and four Afghan National Army soldiers. (Photo by Spc. Hilda Clayton/U.S. Army via AP Photo)

Canadian slackliner Mia Noblet walks on a slackline (25mm wide, 3mm thick and 60m long) during “Tianmen Mountain Female High-Heeled Highline Challenge” at Zhangjiajie National Forest Park on May 27, 2018 in Zhangjiajie, Hunan Province of China. 23-year-old Canadian slackliner Mia Noblet became the first one who finished the challenge in 22 minutes and 36 seconds while 32-year-old French slackliner Mini Guesdon broke the record in 9 minutes and 24 seconds during her second attempt on Sunday. (Photo by VCG/VCG via Getty Images)

A plane battling the Ferguson Fire passes the setting sun in unincorporated Mariposa County Calif., near Yosemite National Park on Sunday, July 15, 2018. (Photo by Noah Berger/AP Photo)

Donald Trump is flanked by Playmates at a party celebrating Playboy magazine's 45th anniversary at the Life Club in New York on December 3, 1998. (Photo by Richard Corkery/NY Daily News Archive via Getty Images)

A communal worker removes the snow from steps next people dressed as pandas near the center of the Ukrainian capital Kiev, on November 14, 2018, during an heavy snowfall, the first one of this autumn season. (Photo by Sergei Supinsky/AFP Photo)