Cairo-based artist Chanel Arif's paints for her art project called After Dinner that uses humans and their surroundings as her canvas, in her gallery in the capital of Cairo, Egypt March 2, 2017. (Photo by Sherif Fahmy/Reuters)

In this photo provided by Mickey Nuttall, members of an international team of skydivers join hands, flying head-down to build their world record skydiving formation, Friday, July 31, 2015, over Ottawa, Ill. (Photo by Jason Peters via AP Photo)

A commuter gestures to Boris Johnson as he rides across Vauxhall Bridge in London, England on November 19, 2015. The London mayor was opening a cycle superhighway. (Photo by John Stillwell/PA Wire)

A woman smokes marijuana during the annual 4/20 marijuana rally on Parliament Hill in Ottawa, Ontario, Canada, April 20, 2017. (Photo by Chris Wattie/Reuters)

People take photos as an Ariane 5 space rocket with a payload of four Galileo satellites lifts off from ESA's European Spaceport in Kourou, French Guiana, on November 17, 2016. Ariane 5 successfully launched on November 17 four satellites which will be part of the Galileo global satellite navigation system. (Photo by Jody Amiet/AFP Photo)

The sculpture “It Takes Two to Tango” by Scottish sculptor David Mach is seen in front of the headquarters of the CMA-CGM shipping company office tower in the port of Marseille, France, March 15, 2016. (Photo by Jean-Paul Pelissier/Reuters)

Indian dancers paint their body like tigers as they perform a Tiger dance during the International day of the Tiger in Calcutta, India, July 29, 2015. Students of Calcutta are taking part in an awareness campaign aiming to draw attention to the threats that tigers face due to habitat loss and poaching. (Photo by Piyal Adhikary/EPA)