Inside the Afar Triangle in Ethiopia’s Danakil desert, camel caravans are used to carry salt. For centuries, the essential mineral has been mined by the Afar people, known for their ability to withstand extremes. The terrain is rugged, travelers are scarce and so are motor vehicles, where the average annual temperature is the highest in the world, and can rise to 122 degrees Fahrenheit, 50 degrees Celsius. (Photo by Ziv Koren/Polaris)

Gorillas sit next to a ruler during a photocall for the annual weigh-in at London Zoo in London, Britain August 24, 2017. During the weigh-in, animals across the zoo have their vital statistics recorded including their height and weight and the information is then shared with zoos across the world to help zookeepers compare important information on thousands of endangered species. (Photo by Neil Hall/Reuters)

Participants dance during the West Indian Day Parade in the Brooklyn borough of New York September 5, 2016. The Labor Day Carnival (or West Indian Carnival) is an annual celebration held on American Labor Day (the first Monday in September) in Crown Heights, Brooklyn, in New York City. (Photo by Eric Thayer/Reuters)

Two dancers pass each other as they compete in a heat during the All Scotland Championships in Irish Dancing at the Royal Concert Hall in Glasgow, Scotland. The championships attract over 2000 dancers from more than 300 dance schools, from countires such as North America, South Africa, Australia and Russia. (Photo by David Moir/Reuters)

Billy Zane and Jasmina Hdagha attend the world premiere of Titanic 3D at The Royal Albert Hall on March 27, 2012 in London, England. (Photo by Dave Hogan/Getty Images)

Members of the 2013 “Jarl Squad” take part in the annual Up Helly Aa festival which culminates in the burning of a Viking Galley in Lerwick, Shetland Islands on January 29, 2013. Up Helly Aa celebrates the influence of the Scandinavian Vikings in the Shetland Islands and has employed this theme in the festival since 1870. The event culminates with up to 1,000 “guizers” (men in costume) throwing flaming torches into their Viking longboat. (Photo by Andy Buchanan/AFP Photo)

Dutch artist Maxim Gazendam works on his sand sculpture during the third edition of the European Championship Sand Sculpting 2014 in Zandvoort aan Zee, The Netherlands, 08 August 2014. Eight sculptors from different European countries will each create an impressive sculpture on the main theme “Music and Dance”. (Photo by Remko De Waal/EPA)

A team from Woody's Ice Cream shop wrangle a large inflatable dinosaur down the street during the Independence Day Parade in Fairfax, Virginia July 4, 2015. Americans marched in star-spangled parades, ran relay races, gathered for fireworks shows and crowned a new world hot dog eating champion as they celebrated Independence Day in traditional style on Saturday. (Photo by Jonathan Ernst/Reuters)