People walk on a sightseeing platform in Zhangjiajie, Hunan Province, China, August 1, 2016. China has opened a 100-metre-long glass skywalk stretching around a cliff on the side of the Tianmen Mountain. The skywalk provides a view of a 300-metre drop and overlooks Tongtian Avenue, a mountain road with 99 turns that snakes up the mountain. When translated in English, it means “Avenue to the Sky”. (Photo by Reuters/Stringer)

Athletes attend training session at the Ak Bulak Nordic Arena outside Almaty, Kazakhstan, July 16, 2015. Kazakhstan is aspiring to host the 2022 Winter Olympics but many in the Central Asian nation view the bid as yet another vanity project of long-ruling President Nursultan Nazarbayev. Almaty, the financial capital, will go head-to-head with the Chinese metropolis Beijing on Friday when the International Olympic Committee elects the winner at its session in Malaysia. (Photo by Shamil Zhumatov/Reuters)

Photographer Frank Relle takes long-exposure images of houses in New Orleans. Says Relle, “The city at night comes alive for me. I imagine stories about the people’s lives inside the homes based on the evidence on the outside. My photographs become a portrait without the person. The night obscures details and the lack of information gives possibility”. Photo: “Telemachus”. Farragut Street, New Orleans, La. Nov. 2006. (Photo by Frank Relle)

Revellers celebrate moments before the rocket fire or “Txupinazo” marks the start of the Festival of San Fermin (or Sanfermines) at Consistorio square in Pamplona, Spain, 06 July 2014. The annual nine day long running-with-the-bulls fiesta commemorates St. Fermin, Pamplona's patron saint. (Photo by Javier Lizin/EFE)

A swimmer disguised as Superman dives into the lake during the 78th “Coupe de Noel” (Christmas cup) swimming race in the Lake Geneva, on December 18, 2016 in Geneva. More than 1800 participants took part in the event, a 12-meter-long swimming off the Geneva's bank in the 7 degrees Celsius cold water. (Photo by Fabrice Coffrini/AFP Photo)

Teeming with images of spectacular underwater scenes from around the world, Call of the Blue is the culmination of a five-year project by the photographer and ocean conservationist Philip Hamilton. This groundbreaking book includes contributions from acclaimed scientists and ocean “guardians”, who reveal what drove them to answer the call of the blue. (Photo by Philip Hamilton/The Guardian)

Yan Zhengming (R), 94, and his wife Zhou Suqing (C), 90, attend their wedding ceremony at their home, on the 70th anniversary of their marriage, in Quxian county of Dazhou, Sichuan province, China, May 15, 2015. The wedding, organized by local charity groups, was a long-time wish of veteran of the World War Two Yan, who married Zhou 70 years ago, but could not afford to have a wedding ceremony, local media reported. (Photo by Reuters/Stringer)

Sukaregang in Garut district, West Java, has long been a bustling center for Indonesia's leather trade, with some shops producing and selling various goods – including bags, shoes and jackets – since the 1940s. The industrial area is also a major supplier for high-end brands from across the globe, catering to the fashion, auto and motor-sports industry. Here: a man walks across a vat of water used to wash the hide. (Photo by Rezza Estily/JG Photo)