Thailand's King Bhumibol Adulyadej in serious portrait January 01, 1960. Thailand's Royal Palace said on Thursday, October 13, 2016, that Thailand's King Bhumibol Adulyadej, the world's longest-reigning monarch, has died at age 88. (Photo by John Dominis/The LIFE Picture Collection/Getty Images)

Waura Indians wrestle during this year's “quarup”, a ritual held over several days to honour in death a person of great importance to them, in Xingu National Park, Mato Grosso State, Brazil August 25, 2013. (Photo by Ueslei Marcelino/Reuters)

A member of a local swimming club holds a Russian national flag as he dives in at the start of a 24-hour swimming marathon near the western Siberian city of Barnaul March 29, 2014. Thirty members of the club will swim in turn during the event, held to mark Crimea becoming part of Russia, local media reported. (Photo by Andrei Kasprishin/Reuters)

A general view showing the shipwrecked cruise ship Costa Concordia in an upright position after the salvage operations in Giglio island, Italy, 17 September 2013. Salvage crews pulled off a major engineering feat when they straightened the listed Costa Concordia cruise ship from the rocks it had been wedged against for the past 20 months. The delicate operation took 19 hours and was completed at 4 am (0200 GMT). The vessel ran aground near the island of Giglio, in Tuscany, in an accident that made world-wide news. (Photo by Angelo Carconi/EPA)

A protester throws a stone towards a burning police bus in front of him, during clashes with police, in central Kiev, Ukraine, Sunday, January 19, 2014. Hundreds of protesters on Sunday clashed with riot police in the center of the Ukrainian capital, after the passage of harsh anti-protest legislation last week seen as part of attempts to quash anti-government demonstrations. The violent scenes further escalated this ex-Soviet republic's political crisis and showed a rift among opposition leaders, one of whom fought bravely to stop the violence, while others condemned the events from afar. (Photo by Evgeny Feldman/AP Photo)

A man walks though Times Square in high heels during unseasonably warm weather on Christmas Eve in the Manhattan borough of New York December 24, 2015. (Photo by Carlo Allegri/Reuters)

Roof-topping enthusiast Daniel Lau takes a selfie with high-rise buildings down below as he stands on the top of a skyscraper in Hong Kong, China on August 15, 2017. A craze that began in Russia has now taken hold in Hong Kong, one of the world's most vertical cities. Mr Lau said he had been inspired by Russian climbers and that he was unafraid of the vertiginous heights he scales. (Photo by ImagineChina/Rex Features/Shutterstock)

Cave Diver, Anhumas Abyss, Bonito, Brazil: The Anhumas Abyss is an underground cavern with a crystal-clear lake below, more than 260 feet (79 m) deep. A visitor must enter through a narrow opening at the top of the chamber and rappel into the cave. Snorkeling and scuba diving in the lake reveal amazing scenery. Distinctive, conical limestone stalagmites and stalactites occupy the lake and the surrounding area, some reaching 65 feet (20 m) high. (Photo by Marcio Cabral/Nature’s Best Photography Awards 2017)