Student protestors, including one girl with a camera, struggle with soldiers from the Chinese Army, the PLA. Tiananmen Square, 1989. (Photo by Jeff Widener/Associated Press)

The student Patricia Vasconcellos de Almeida, 22, tried to kiss one of the military police who formed a cordon ostensibly in front of the building Fetranspor (Federation of Transport Companies), in Rio de Janeiro, on June 27, 2013. (Photo by Zulmair Rocha/UOL)

A white whale wears a wreath at the Hakkeijima Sea Paradise aquarium-amusement park complex in Yokohama, Japan, on October 3, 2012. (Photo by Associated Press)

Venezuela's food shortages, inflation and crumbling medical sector have become such a source of anguish that a growing number of young women are reluctantly opting for sterilizations rather than face the hardship of pregnancy and child-rearing. Traditional contraceptives like condoms or birth control pills have virtually vanished from store shelves, pushing women towards the hard-to-reverse surgery. While no recent national statistics on sterilizations are available, doctors and health workers say demand for the procedure is growing. (Photo by Carlos Garcia Rawlins/Reuters)

Mark Dill and Brit Thacker practice acro-yoga as approximately 70,000 people from all over the world gather for the 30th annual Burning Man arts and music festival in the Black Rock Desert of Nevada, U.S. August 29, 2016. (Photo by Jim Urquhart/Reuters)

Indian women wearing traditional attire take a “selfie” with an Indian man dressed as King 'Mahabali' during the Hindu harvesting festival Onam celebrations in Bangalore, India, 28 August 2015. Local people put flower mats in front of their houses, to welcome the King Mahabali, a past ruler of Kerala southern India, during the ten-day festival. (Photo by Jagadeesh N. V./EPA)

A protester jumps on the table in front of the European Central Bank President Mario Draghi during a news conference in Frankfurt, Germany April 15, 2015. (Photo by Kai Pfaffenbach/Reuters)

Expedition 44 flight engineer and NASA astronaut Scott Kelly seen inside the Cupola, a special module which provides a 360-degree viewing of the Earth and the International Space Station. Kelly is one of two crew members spending an entire year in space. (Photo by Scott Kelly/NASA)