A boy carries empty sacks after bringing different types of plastic materials to a recycling station in Khartoum North April 16, 2015. People bring bottles and other plastic materials to the station for recycling, and get paid in return. (Photo by Mohamed Nureldin Abdallah/Reuters)

Some women doing yoga pose on the hammocks during the Anti-Gravity yoga class at Svarga e-Motion Sanctuary at Dharmawangsa Square, Jakarta, Saturday, April 18, 2015. Anti-Gravity Yoga or “aerial yoga”, is a new type of yoga, originating in New York but now being practised in several countries, which combines the traditional yoga poses, pilates and dance with the use of a hammock. (Photo by Jurnasyanto Sukarno/JG Photo)

A girl looks out from the window of a “La Sabana” tourist train in La Caro March 1, 2015. The “La Sabana” tourist train that runs through the capital was founded by Eduardo Rodriguez, a railway engineer. Rodriguez has worked on Colombia's railway system his whole life and now, with an air of nostalgia, transports thousands of tourists in renovated steam locomotives that he fixes in Bogota's Central Station which dates back to 1913. (Photo by Jose Miguel Gomez/Reuters)

2016 Rio Olympics, Handball, Preliminary, Women's Preliminary Group B Netherlands vs France, Future Arena, Rio de Janeiro, Brazil on August 6, 2016. Lois Abbingh (NED) of Netherlands celebrates a goal. (Photo by Marko Djurica/Reuters)

2016 Rio Olympics, Beach Volleyball, Women's Preliminary, Beach Volleyball Arena, Rio de Janeiro, Brazil on August 6, 2016. Liliana Fernandez Steiner (ESP) of Spain prepares to serve. (Photo by Ruben Sprich/Reuters)

People cool off at the water park during the “Circuit” the international gay festival in Vilassar de Dalt, Spain, Tuesday, August 9, 2016. The special international event has attracted many thousands and the gay festival “Circuit” runs until August 14. (Photo by Manu Fernandez/AP Photo)

This photo taken on August 7, 2016 shows mahjong enthusiasts playing mahjong under water in a swimming pool at a diving club in the Chinese city of Chongqing. Only participants with proper diving certification were allowed to take part in the underwater competition. (Photo by AFP Photo/Stringer)

Children attend a swim training session at Hangzhou Chen Jinglun Sport school Natatorium, where Chinese Olympic swimmer Sun Yang and Fu Yuanhui also trained, in Hangzhou, Zhejiang province, China, August 10, 2016. (Photo by Aly Song/Reuters)