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)

Shepherds walk with sheep through the village on their way home during autumn redyk in Gron, Tatra Mountains region of southern Poland, October 6, 2015. Redyk is a traditional, kilometres-long march of highlanders with flocks of sheep, which takes place twice a year: in the spring at the start of the grazing season, and in the autumn at season's end. (Photo by Kacper Pempel/Reuters)

Model Bella Hadid poses on the red carpet of Rihanna's new Savage X Fenty collection show for New York Fashion Week at the Barclays Center in the Brooklyn borough of New York, U.S., September 10, 2019. (Photo by Shannon Stapleton/Reuters)

Actress Maddie Ziegler holds her bag as she poses during People's “Ones To Watch” event celebrating Hollywood's rising and brightest stars in West Hollywood, California September 16, 2015. (Photo by Kevork Djansezian/Reuters)

Edward Nunn of the USA, Toney Freeman of the USA and Dexter Jackson of the USA pose during the IFBB Australia Pro Grand Prix XII at The Plenary on March 9, 2013 in Melbourne, Australia. (Photo by Robert Cianflone)

Russia' s Tiffani Zagorski and Russia' s Jonathan Guerreiro compete in the ice dance free dance of the figure skating event during the Pyeongchang 2018 Winter Olympic Games at the Gangneung Ice Arena in Gangneung on February 20, 2018. (Photo by Lucy Nicholson/Reuters)

Migrating gray cranes, on November 30, 2009 around the Hula Lakes in northern Israel. (Photo by Uriel Sinai/Getty Images)

Two baby orangutans play with each other at the wildlife department in Kuala Lumpur, Malayasia, October 19, 2015. The Malaysian wildlife department in July seized two baby Sumatran orangutans, found in duffel bags, from traffickers who were attempting to sell them to buyers in Malaysia. According to local media, the orangutans will be returned to Medan, Indonesia on Tuesday. The illegal wildlife trade is estimated to be $8 billion a year worldwide, according to TRAFFIC, a wildlife trade monitoring network. (Photo by Olivia Harris/Reuters)