A woman doing yoga at a fountain, in downtown Stuttgart, Germany, Thursday, June 22, 2017. Weather forecasts predict hot summer weather as well as thunderstorms for some parts of Germany. (Photo by Marijan Murat/DPA via AP Photo)

Nick Franklin, in action during the FMX competition at the 23rd edition of Free4Style this Saturday, July 2, 2016 in Estavayer-le-Lac,Switzerland. (Photo by Jean-Christophe Bott/Keystone/APA)

A 40-foot sculpture of the swimmer Rebecca Adlington was unveiled at the Serpentine in London’s Hyde Park on July 25, 2016 to launch a campaign by Kelloggs to encourage the public to support Team GB at the Rio Olympics. (Photo by David Parry/PA Wire/Barcroft Images)

Heavy artillery on parade during a review of the Moscow Garrison troops during the May Day celebrations in Red Square, passing posters of Lenin and Stalin. (Photo by N. Sitnikov/Hulton Archive/Getty Images). 1st May 1947

Yang Juan, an employee at Goopal Group, takes a nap in her seat after lunch, in Beijing, China, April 21, 2016. Office workers sleeping on the job is a common sight in China, where a surplus of cheap labour can lead to downtime at work. But in China's technology sector, where business is growing faster than many start-up firms can hire new staff, workers burn the midnight oil to meet deadlines and compete with their rivals. Some companies provide sleeping areas and beds for workers to rest during late nights. (Photo by Jason Lee/Reuters)

Street entertainer and fortune teller “Juana La Cubana” smiles holding a cigar in her mouth as she waits for tourists in Havana, Cuba, Sunday, May 24, 2015. Juana is 72 years old and has worked in the Cathedral square in Old Havana for 28 years. (Photo by Desmond Boylan/AP Photo)

Tourists take a panoramic view of Kuala Lumpur from a skybox during a media preview at Kuala Lumpur Tower in Kuala Lumpur, Malaysia, 05 May 2016. Skybox, 421 metres above ground level will be the latest tourists attraction at Kuala Lumpur Tower, the 7th tallest freestanding tower in the world. (Photo by Ahmad Yusni/EPA)

Mount Sinabung volcano erupts, as seen from Tiga Pancur village, Karo Regency in Indonesia's North Sumatra province October 8, 2014. (Photo by Y. T. Haryono/Reuters)