A boy sits on the back of a crocodile on May 19, 2018 at a pond in Bazoule in Burkina Faso, a village which happily shares its local pond with “sacred” crocodiles. Crocodiles may be one of the deadliest hunters in the animal kingdom, but in a small village in Burkina Faso it is not unusual to see someone sitting atop one of the fearsome reptiles. According to local legend, the startling relationship with the predators dates back to at least the 15 th century. The village was in the grip of an agonising drought until the crocodiles led women to a hidden pond where the population could slake their thirst. (Photo by Olympia de Maismont/AFP Photo)

Marieke van der Meer from the Netherlands works on her sculpture “Flora” at the sand sculpture show in Binz on Ruegen island, Germany, 09 March 2016. With the motto “Fascination Nature”, 50 sand artists have created oversized sculptures. The sculptors use 16,000 tons of special sand that is pressed into big blocks first and then formed. The 7th sand sculpture show on 5,600 square meters of exhibition ground opens on 12 March 2016. (Photo by Ens Buettner/EPA)

“Woman with Umbrella in Rain” by Raimund von Stillfried. Artist: Kusakabe Kimbei (Japanese, 1841–1934), 1870s. Commercial photography studios in Meiji-era Japan were renowned for the subtlety and refinement of their coloring techniques. This hand-tinted image of a young woman caught in a heavy rainstorm achieved its naturalistic effect by knitting together multiple strands of artifice: the greenery in the foreground was a studio prop; the flaps of the kimono were suspended by thin wires to create the impression of a strong wind; and long, diagonal marks were made on the negative to suggest streaks of rain. (Photo courtesy of The Metropolitan Museum of Art)

A boy rides on a snow wagon towed by a robot dressed as a Teddy bear, which only moves forward by moving its legs, during the Ice and snow carnival at Taoranting park in Beijing February 9, 2015. (Photo by Kim Kyung-Hoon/Reuters)

Chinese aids activists hand out condoms in a subway train in Wuhan, central China's Hubei province on December 1, 2014. The World Health Organization issued a call to action to China on December 1, 2014 over HIV/AIDS as government figures said nearly half a million people are living with the disease or its precursor, with hundreds of thousands more thought to be undiagnosed. (Photo by AFP Photo)

Hotel staff practice self-defence skills after a training session given by team member of Special Weapons and Tactics (SWAT) team, in Hangzhou, Zhejiang province, April 7, 2016. (Photo by Reuters/Stringer)

The Boeoegg, a giant symbolic snowman made of wadding and and filled with firecrackers burns on top of a bonfire in Sechselaeuten square on April 24, 2017 in Zurich. When the bells of the Saint Peter's church chime six o'clock, the bonfire under the snowman is set in fire and the guildsmen wearing historical costumes ride around the bonfire. The faster the head of the snowman explods the warmer and more beautiful the summer will be. (Photo by Michael Buholzer/AFP Photo)

Demonstrators clash with members of the Bolivarian National Police as protests continue in Caracas, Venezuela, 20 April 2017. The Bolivarian National Guard, using tear gas, tried to disperse protests against the government of Venezuelan President Nicolas Maduro. (Photo by Miguel Gutierrez/EPA)