“The Challenge!” Young boy relishes in a game of tug of war before school. Photo location: Lake Titicaca, Peru. (Photo and caption by Paul Heyman/National Geographic Photo Contest)

A Siberian tiger at a photographer for getting too much in its face during the presentation of two new Siberian tigers at Cabarceno Natural Reserve in Cabarceno, northern Spain, 21 July 2014. (Photo by Pedro Puente Hoyos/EPA)

A couple stands next to a poster depicting Dutch politician Geert Wilders and Russian President Vladimir Putin kissing, at a metro station in Amsterdam April 3, 2016. (Photo by Cris Toala Olivares/Reuters)

A man poses for a photograph in front of a mural of Democrat US presidential nominee Hillary Clinton clad in a swimsuit bearing the colours of the US flag in West Footscray in Melbourne on July 30, 2016. An Australian mural of US presidential nominee Hillary Clinton in a revealing, stars and stripes swimsuit may be taken down, after it has reportedly been deemed offensive. (Photo by Paul Crock/AFP Photo)

One-year-old female giant panda cub Nuan Nuan reacts inside her enclosure during joint birthday celebrations for the panda and its ten-year-old mother Liang Liang at the National Zoo in Kuala Lumpur on August 23, 2016. Giant pandas Liang Liang, aged 10, and her Malaysian-born cub Nuan Nuan, 1, were born on August 23, 2006 and August 18, 2015 respectivetly. (Photo by Mohd Rasfan/AFP Photo)

Ja Kang Song, 71, and Ja Hyun Su, 72, dive for shellfish and are the main breadwinners for their families. In South Korea, 45% of the diving women of Jeju are over the age of 70. Routinely diving to depths of 20m and staying under for an average of two to three minutes, the pressure on the body takes its toll and, like many others, burst eardrums have left Ja Hyun Su deaf. Each season, between seven and 10 women die diving the waters around Jeju Island. (Photo by Andy W. Langton/Age International)

In this photo taken on Monday, January 5, 2015, a mallard duck attempts to walk on a frozen pond in Yukon, Okla. (Photo by Steve Gooch/AP Photo/The Oklahoman)

Belgium. Rosalie, 9, goes to school in Brussels. “At my school we have separate toilets for girls and boys on every floor. My classroom is on the 3rd floor. We have 22 toilets, which are shared between 230 pupils and 20 adults. The teachers at school let us go to the toilet whenever we need to”. (Photo by Tim Dirven/WSUP/Panos)