The shadow of a partial eclipse is cast on to the cheek of a student on the roof of the Jana Dlugosza Academy in Czestochowa, Poland March 20, 2015. (Photo by Grzegorz Skowronek/Reuters/Agencja Gazeta)

Shoppers walk down stairs featuring a five-metre-high reproduction of Vincent van Gogh's signature painting “Sunflowers”, at the entrance to Ocean Terminal in Hong Kong July 15, 2013. A premium three-dimensional reproduction of works of Van Gogh, the RELIEVO collection, approved by the curators of the Van Gogh Museum in Amsterdam, is on display at a gallery inside Harbour City shopping mall attached to the terminal. (Photo by Bobby Yip/Reuters)

A trainer tries to convince a dog to jump over an obstacle during the Dog Olympic Games in Rio de Janeiro, Brazil, Sunday, September 18, 2016. Owner of the dog park and organizer of the animal event Marco Antonio Toto says his goal is to socialize humans and their pets while celebrating sports. (Photo by Silvia Izquierdo/AP Photo)

People watch as an acrobat rides his motorcycle around a circular track at an entertainment park set up outside a shrine in Rawalpindi, Pakistan, on June 19, 2013. (Photo by Muhammed Muheisen/Associated Press)