Japanese team trains before the 6th FINA Synchronised Swimming World Trophy at the Water Cube on December 8, 2011 in Beijing, China. (Photo by Feng Li/Getty Images)

Soldiers, including two recruits who have brought some chickens, at Victoria prepare to board the train for the battle front. (Photo by Hulton Archive/Getty Images)

Grand Champion Oakhurst Crusin' in Chrome, an Australian Shepard, poses backstage at the Westminster Kennel Club Dog Show after winning best of opposite s*x on February 13, 2012 in New York City. (Photo by Michael Nagle/Getty Images)

Visitors of the world's longest tree top walk between the trees of the Bavarian forest on November 6, 2009 in Neuschoenau, Germany. The path, 1300 meters long and in 8 to 25m height, winds up to an impressive tower with a height of 44 meters. The wooden construction is integrated into the forest and delivers a natural experience. (Photo by Miguel Villagran/Getty Images)

A dejected German Grenadier carrying a machine gun on his shoulder in front of a building on fire during the German retreat in Russia. (Photo by Keystone/Getty Images). 1944

A woman carries her child, both wearing traditional red clothes celebrating the Chinese Lunar New Year in Bangkok February 19, 2015. (Photo by Damir Sagolj/Reuters)

Ukraine's Hanna Antonova competes during the 2015 World Pole Dance Championships held in Beijing, Sunday, April 12, 2015. (Photo by Ng Han Guan/AP Photo)

The Y-40 Deep Joy is the worlds deepest pool. Y-40 is projected by Architect Emanuele Boaretto and supported by the “Boaretto Group Hotel and Resort”. The name Y-40 is inspired by mathematical symbols. “Y” is the ordinate axis of the Cartesian system and “–40” means the world's record depth or our pool- that is 40 meters underground. (Photo by Courtesy Y40 Deep Joy)