Guests have breakfast as another guest climbs to gather at the Skylodge Adventure Suites in the Sacred Valley in Cuzco, Peru, August 14, 2015. Tourists taking on an arduous climb up the steep cliff face of Peru's Sacred Valley are being rewarded for their efforts by being able to spend the night in transparent mountaintop sleeping pods at the “Skylodge Adventure Suites”. To reach the pods, visitors need to climb 400 metres of via ferrata (a steel cable and rungs) up the valley side or hike an intrepid trail through zip lines. (Photo by Pilar Olivares/Reuters)

An environmental activist adjusts his mask while taking part in “The Dead Sea Swim Challenge”, swimming from the Jordanian to Israeli shore, to draw attention to the ecological threats facing the Dead Sea, in Kibbutz Ein Gedi, Israel November 15, 2016. Swimmers from around the world plunged into the salty waters of the Dead Sea on Tuesday to attempt a seven-hour swim across the fabled lake in a bid to draw attention to its environmental degradation. Wearing protective masks and snorkels, 25 swimmers paddled through the muddy water to attempt the 9-mile (15-kilometer) swim from Jordan to Israel. (Photo by Nir Elias/Reuters)

A cadet from the Interior Ministry with the word Fidel painted on her face attends a rally honoring the late Cuban leader at the Revolution Plaza in Havana, Cuba, Tuesday, November 29, 2016. Schools and government offices were closed Tuesday for a second day of homage to Fidel Castro, with the day ending in a rally on the wide plaza where the Cuban leader delivered fiery speeches to mammoth crowds in the years after he seized power.Fidel Castro passed away Friday Nov. 25. He was 90. (Photo by Ramon Espinosa/AP Photo)

Fighters of the Free Syrian Army fire an anti-aircraft weapon in the rebel-held Mashhad area in southeastern Aleppo, on December 12, 2016, as they battle Syrian government forces during an operation to retake the embattled city. The crucial battle for Aleppo entered its “final phase” after Syrian rebels retreated into a small pocket of their former bastion in the face of new army advances. The retreat leaves opposition fighters confined to just a handful of neighbourhoods in southeast Aleppo, the largest of them Sukkari and Mashhad. (Photo by AFP Photo/Stringer)

A woman uses a virtual reality (VR) headset to view images by Mexican painter Frida Kahlo in Mexico City, Mexico, 23 May 2018. The technological giant Google launched the “The Faces of Frida”, an interactive digital exhibition that treasures the heartrending work of the Mexican artist to tell her story from different points of view, with attention to the invisible details. (Photo by Sashenka Gutierrez/EPA/EFE)

This year’s World Nomad Games, a celebration of nomadic heritage, took place in the Issyk-Kul province of Kyrgyzstan. Eleanor Moseman photographed female competitors who had travelled from all over central Asia and eastern Europe, and explored the difficulties and challenges they face as competitors. (Photo by Eleanor Moseman/The Guardian)