Students celebrate their A-level results at King Edward VI High School for Girls in Birmingham, England on August 18, 2016. The proportion of top grades achieved by A-level students across the UK has fallen for a fifth year in a row, and girls have caught up with boys in attaining A* grades. (Photo by Joe Giddens/PA Wire)

“Asaro from the Eastern Highlands”. The mudmen could not cover their faces with mud because the people of Papua New Guinea thought that the mud from the Asaro river was poisonous. So instead of covering their faces with this alleged poison, they made masks from pebbles that they heated and water from the waterfall, with unusual designs such as long or very short ears either going down to the chin or sticking up at the top, long joined eyebrows attached to the top of the ears, horns and sideways mouths. (Photo and caption by Jimmy Nelson)

A man takes a picture of sea spray as storms hit Cape Town, South Africa, June 7, 2017. (Photo by Mike Hutchings/Reuters)

Highly commended, mammals: Gelada after the storm – Marco Gaiotti (Italy). “Gelada baboons are the only monkey species in the world that feed on grasses. They are native to the tableland of Ethiopia. Every morning large family groups wander from their sleeping places in the steep rock face, up to 1,000 metres high, to the feeding grounds at the tablelands. This image clearly depicts their feeding strategy: they pull out bunches of grass, sort the stalks and then lift them to their mouth. This shot was taken towards the end of the rainy season after a heavy storm”. (Photo by Marco Gaiotti/2019 GDT European Wildlife Photographer of the Year)

Photos of Edward Snowden, a contractor at the National Security Agency (NSA), and U.S. President Barack Obama are printed on the front pages of local English and Chinese newspapers in Hong Kong in this illustration photo June 11, 2013. Snowden, who leaked details of top-secret U.S. surveillance programs, dropped out of sight in Hong Kong on Monday ahead of a likely push by the U.S. government to have him sent back to the United States to face charges. (Photo by Bobby Yip/Reuters)

In this February 7, 2014 file photo, Matt Figi hugs and tickles his once severely-ill seven year old daughter Charlotte, as they walk together inside a greenhouse for a special strain of medical marijuana known as Charlotte's Web, which was named after the girl early in her treatment for crippling severe epilepsy, in the mountains west of Colorado Springs, Colo. Colorado is poised to award more than $8 million for medical marijuana research, a step toward addressing complaints that little is known about pot's medical potential. Among the research projects poised for approval on Wednesday, December 17, 2014, are one for pediatric epilepsy patients, and another for children with brain tumors. (Photo by Brennan Linsley/AP Photo)

New York City Deputy Police Commissioner John A. Leach, right, watching agents pour liquor into sewer following a raid during the height of prohibition, circa 1921. (Photo by Tom Marshall/Mediadrumworld)

U.S. President elect Barack Obama kisses his wife Michelle as Vice-President elect Joe Biden (right) embraces his wife Jill after Obama gave his victory speech during an election night gathering in Grant Park on November 4, 2008 in Chicago, Illinois. (Photo by Scott Olson/Getty Images)