The NASA Extreme Environment Mission Operations (NEEMO) 21 mission began on July 21 as an international crew of aquanauts splashed down to the undersea Aquarius Reef Base, located 62 feet below the surface of the Atlantic Ocean in the Florida Keys National Marine Sanctuary. The NEEMO 21 crew will perform research both inside and outside the habitat during a 16-day simulated space mission. During simulated spacewalks carried out underwater, they will evaluate tools and mission operation techniques that could be used in future space missions, including journeys to Mars. (Photo by Karl Shreeves/NASA)

This picture taken on November 1, 2014 shows Japanese body-painting artist Hikaru Cho (L) adding the finishing touches to a body painting of fingers sticking out from prison cell bars on the head of Ryonosuke Tanaka during “Tokyo Designers Week” in Tokyo. Cho, 21, was born to Chinese parents in Japan and burst onto Tokyo's art scene when she entered the city's Musashino Art University in 2012. Cho's ultimate ambition is to paint an entire – and naked – body. (Photo by Yoshikazu Tsuno/AFP Photo)

Russian Police academy female cadets march during a rehearsal for the Victory Day military parade at Dvortsovaya (Palace) Square in St Petersburg, Russia, Wednesday, May 7, 2014. Victory Day, marking the defeat of Nazi Germany, is Russia's most important secular holiday celebrated on May 9. (Photo by Dmitry Lovetsky/AP Photo)

A red fox sits in front of a Eurofighter Typhoon combat jet on the grounds of the 2014 ILA Berlin Air Show, in Selchow near Schoenefeld, Germany, Thursday, May 15, 2014. The International Aviation and Aerospace Exhibition ILA will take place from May 20 until May 25, 2014. (Photo by Patrick Pleul/AP Photo/DPA)

Children react after what activists said was shelling by forces loyal to Syria's President Bashar al-Assad near the Syrian Arab Red Crescent center in the Douma neighborhood of Damascus May 6, 2015. (Photo by Bassam Khabieh/Reuters)

Ugly dog contestants Sweepee Rambo and owner Jason Wurtz celebrate in winning the 2016 World's Ugliest Dog Contest at the Sonoma-Marin Fair in Petaluma, California, USA, 24 June 2016. (Photo by Peter Dasilva/EPA)

An employee feeds a one-week-old coati cub with a bottle of milk at the Royev Ruchey zoo in the suburbs of Krasnoyarsk, Siberia, October 10, 2014. The mother of three cubs refused to nurse them, according to zoo employees. (Photo by Ilya Naymushin/Reuters)

Robert Galvan, who is on death row for murder, speaks to members of the media at the Adjustment Center yard during a media tour of California's Death Row at San Quentin State Prison in San Quentin, California December 29, 2015. America's most populous state, which has not carried out an execution in a decade, begins 2016 at a pivotal juncture, as legal developments hasten the march toward resuming executions, while opponents seek to end the death penalty at the ballot box. (Photo by Stephen Lam/Reuters)