U.S. Army soldiers with the 1st Battalion, 501st Infantry Regiment deployed to Combat Outpost Sabari, Afghanistan scan their area as they begin a multi-day air assault mission near the Pakistani border of eastern Afghanistan's Khost province May 2, 2012. (Photo by Staff Sgt. Joshua L. DeMotts/U.S. Air Force)

Police officers control the crowd (rear) while surrounding a man (front C) suspected to be involved in opening fire on a beachside hotel in Sousse, Tunisia, as a woman reacts (R), June 26, 2015. At least 27 people, including foreign tourists, were killed when at least one gunman opened fire on a Tunisian beachside hotel in the popular resort of Sousse on Friday, an interior ministry spokesman said. Police were still clearing the area around the Imperial Marhaba hotel and the body of one gunman lay at the scene with a Kalashnikov assault rifle after he was shot in an exchange of gunfire, a security source at the scene said. (Photo by Amine Ben Aziza/Reuters)

General view at the Red Bull Music Academy x Mangrove float at Notting Hill Carnival on August 28, 2017 in London, England. The Notting Hill Carnival has taken place since 1966 and now has an attendance of over two million people. (Photo by Tristan Fewings/Getty Images for RedBull)

Bonobo apes, primates unique to Congo and humankind's closest relative, groom one another at a sanctuary just outside the capital Kinshasa, Congo on October 31, 2006. (Photo by Finbarr O'Reilly/Reuters)

An aerial view taken with a drone shows the autumnally colored Fuerst-Pueckler-Park near Cottbus, eastern Germany, Saturday, October 29, 2016. The park, composed with great sensitivity in the 19th century by Prince Hermann von Pueckler-Muskau, is considered as one of the last great German landscape gardens. (Photo by Patrick Pleul/DPA via AP Photo)

Parts of the Royal Chariot, which will be used during the late King Bhumibol Adulyadej's funeral later this year is seen at the National Museum in Bangkok, Thailand, February 6, 2017. (Photo by Chaiwat Subprasom/Reuters)

Happiness on a Rainy Day by Fardin Oyan, Bangladesh. Winner of the young environmental photographer of the year. Many children in Bangladesh love to bathe and play in the rain. The country, which is flat and occupied by the huge Ganges-Brahmaputra Delta, is exposed to floods, especially during monsoon season. (Photo by Fardin Oyan/2018 Ciwem environmental photographer of the year 2018)

Two women lighting cigarettes on a tennis court in Essex, England circa 1930's. (Photo by Keystone View/FPG/Getty Images)