North Korean soldiers keep watch at the bank of the Yalu River, near the North Korean town of Sinuiju, opposite Dandong in China's Liaoning province, September 10, 2016. (Photo by Thomas Peter/Reuters)

A hostage runs towards a police officer outside Lindt cafe, where other hostages are being held, in Martin Place in central Sydney December 15, 2014. Two more hostages have run out of the cafe at the center of a siege in Sydney, Australia's largest city, according to a Reuters witness at the site. The two women were both wearing aprons indicating they were staff at the Lindt cafe where a gunman has been holding an unknown number of hostages for several hours. Three men had earlier run out of the cafe. (Photo by Jason Reed/Reuters)

Female sea lion “Sarasa” holds a hose with her mouse to help a trainer clean her room at the Shinagawa Aqua Stadium aquarium in Tokyo on December 30, 2014. The aquarium is carrying out year-end general cleaning of their facilities. (Photo by Yoshikazu Tsuno/AFP Photo)

People look at a loaded truck that got stuck in a sinkhole on a road in Guilin, Guangxi Zhuang Autonomous Region, January 7, 2015. No injury was reported, according to local media. (Photo by Reuters/Stringer)

Chinese Kazakh eagle hunters sit on horseback as they travel to a local competition on January 29, 2015 in the mountains of Qinghe County, Xinjiang, northwestern China. The festival, organised by the local hunting community, is part of an effort to promote and grow traditional hunting practices for new generations in the mountainous region of western China that borders Kazakhstan, Russia and Mongolia. The training and handling of the large birds of prey follows a strict set of ancient rules that Kazakh eagle hunters are preserving for future generations. (Photo by Kevin Frayer/Getty Images)

NASA handout photographs from the various Apollo missions are shown in this combination photograph. The photographs are some of more than 12,000 from NASA's archives recently aggregated on the Project Apollo Archive Flickr account. (Top L) David R. Scott, command module pilot, stands in the open hatch of the Command Module during the Apollo 9 mission March 6, 1969. (Top centre) Edwin "Buzz" Aldrin Jr.walks on the surface of the moon during the Apollo 11 mission July 20, 1969. (Top R) Neil Armstrong, Apollo 11 commander, is pictured inside the Lunar Module during the Apollo 11 mission July 20, 1969. (Bottom L) Alan Bean holds a container filled with lunar soil collected during the Apollo 12 mission November 19, 1969. (Bottom centre) Scientist-astronaut Harrison Schmitt rides in the Lunar Roving Vehicle during the Apollo 17 mission December 13, 1972. (Bottom R) Harrison Schmitt stands next to a huge, split boulder during the Apollo 17 mission December 13, 1972. (Photo by Reuters/NASA)

Graffiti is painted on the bathroom walls at a restaurant in the Williamsburg area of Brooklyn borough in New York, United States, October 1, 2015. Some 2.4 billion people around the world don't have access to decent sanitation and more than a billion are forced to defecate in the open, risking disease and other dangers, according to the United Nations. To mark World Toilet Day on November 19, Reuters photographers captured pictures of toilets in cities, towns and villages around the globe. (Photo by Shannon Stapleton/Reuters)