This picture taken on February 16, 2017 in Fangshan village in China's coastal province Fujians, shows a villager performing the “eating flowers” ritual. Villagers in eastern China have a unique way of washing away the taint of evil spirits – by bathing in a shower of scorching sparks. (Photo by Johannes Eisele/AFP Photo)

The world-famous sprinter Usain Bolt, 30, took a break from the track to celebrate Carnival as revellers doused each other with paint in Trinidad and Tobago on February 26, 2017. (Photo by David Wears/Splash News and Pictures)

Tour guides wearing traditional Chinese dress practice smiling by biting chopsticks at Qingming Grand-River Park in Kaifeng, central China's Henan Province on March 2, 2017, aiming to provide better service for visitors. (Photo by IPA Asia via ZUMA Wire)

Brain-on-a-chip. Dazzling in green and magenta this image shows the nerve fibres (in green) produced by neural stem cells (in magenta) as they grow on a synthetic gel. Captured by a technique known as confocal microscopy, the image is part of research shedding light on how tinkering with the environment can affect the way in which nerve fibres grow. (Photo by Collin Edington and Iris Lee/Massachusetts Institute of Technology/Wellcome Images)

In this July 9, 2016 file photo, girls jump from a diving platform into the Geneva Lake and enjoy sunny and warm weather, in Villeneuve, Switzerland. After nearly 90 years, women can legally swim topless in Geneva’s lake and Rhone River without running the risk of a fine. Geneva’s regional council has voted to modify a 1929 ordinance that banned women from swimming topless in the city’s main natural waterways, though the change doesn’t apply to public swimming pools or swimming totally naked. Nicolas Bolle, an official with Geneva’s security department, on Thursday, April 6, 2017 confirmed the council’s action a day earlier. (Photo by Jean-Christophe Bott/Keystone via AP Photo)

In this April 20, 2017 photo, a woman is aided by fellow demonstrators after falling, overcome by tear gas, during anti-government protests in Caracas, Venezuela. Tens of thousands of protesters asking for the resignation of President Nicolas Maduro flooded the streets again, one day after three people were killed and hundreds arrested in the biggest anti-government demonstrations in years. (Photo by Ariana Cubillos/AP Photo)

Participants in the Grelka Fest at the Sheregesh resort in Tashtagolsky District of Kemerovo Oblast, Russia on April 22, 2017. Russian girls marked the end of the ski season with a record-breaking bikini ski festival at Siberia’s top winter resort, Sheregesh. Some 1,498 skiers and snowboarders undressed to impress in the annual event as they took to the pistes under blues skies and sunshine in a bracing temperature of just 5°C. (Photo by Grelka Fest/The Siberian Times)

Cuban girls dressed as nurses and a lizard wait for their turn to dance during a visit by the Gay Men's Chorus of Washington in Havana July 13, 2015. The choir made its first appearance on July 12, 2015 in Cuba as part of a tour that will include a dozen concerts in the context of the restoration of relations between the island and the United States. (Photo by Enrique de la Osa/Reuters)