Labourers stack dried bricks inside a kiln, where they will be fired, at a brick factory on the outskirt of Sanaa, Yemen, June 1, 2016. Traditional mud brick tower houses have always been a source of pride to Yemenis, and over a year into a devastating civil war, they are also providing some much-needed jobs in the ancient capital Sanaa. (Photo by Mohamed al-Sayaghi/Reuters)

Christ the Redeemer is seen from the Vista Chinesa (Chinese View) during sunrise in Rio de Janeiro, Brazil, May 4, 2016. Rio de Janeiro is a marvel and a mess all at once. When it hosts the first ever Olympics in South America, starting Aug. 5, visitors will see a city whose stunning topography – stark, verdant mountains loom over packed and playful beaches – competes only with the drama of daily life here. (Photo by Ricardo Moraes/Reuters)

Mahouts and their elephants display a poster during a campaign ahead of the August 7 referendum in Auytthaya province, north of Bangkok, Thailand, August 1, 2016. Officials across the country are drumming up campaigns to encourage voting on the draft constitution in a referendum on Sunday. (Photo by Chaiwat Subprasom/Reuters)

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)

2016 Rio Olympics, Gymnastics training, Rio Olympic Arena, Rio de Janeiro, Brazil on August 4, 2016. Close up of the feet of Rebecca Downie (GBR) of United Kingdom as she trains on the beam. (Photo by Dylan Martinez/Reuters)

Men carry a dog, wearing a costume and seated on a stool, as a form of respect as they believe that dogs found water for their ancestors, during a local festival for the Miao ethnic minority in Jianhe county, Guizhou Province, China, August 14, 2016. (Photo by Reuters/China Daily)

Pine trees are seen after a forest fire near Sao Pedro do Sul, Portugal August 14, 2016. Deadly wildfires raging for two weeks in Portugal have destroyed a wooded area the size of 100,000 soccer fields, and the small Iberian nation alone accounts for half of all forests burned in the European Union this year. (Photo by Rafael Marchante/Reuters)

Participants react as they climb a greased pole to collect vouchers for gifts during a “Panjat Pinang” event organised in celebration of Indonesia's 71st Independence day in Jakarta, Indonesia August 17, 2016. (Photo by Darren Whiteside/Reuters)