Julian, left, is photographed by his mother with friend Gianluca, right, under water at a public pool in Gelsenkirchen, Germany, on a hot Friday, July 3, 2015. Germany faces a heat wave with temperatures up to 38 degrees Celsius (100 degrees Fahrenheit) at the weekend. (Photo by Martin Meissner/AP Photo)

People look at a RoboThespian humanoid robot at the Tami Intelligence Technology stall at the WRC 2016 World Robot Conference in Beijing, China, October 21, 2016. The conference showcased China's burgeoning robot industry as the nation seeks to increase the use of robots in its manufacturing and service industries. (Photo by Thomas Peter/Reuters)

Bull riders prepare prior to a bull riding event in Santa Tecla, El Salvador, December 15, 2016. (Photo by Jose Cabezas/Reuters)

Costumed participants take a break during a traditional Perchtenlauf (Perchten parade) in Osterseeon near Munich, Germany, December 17, 2016. (Photo by Michaela Rehle/Reuters)

A woman dressed up as a zombie participates in a zombie walk in Stockholm, Sweden on August 19, 2017. (Photo by Jonathan Nackstrand/AFP Photo)

“Not for the faint of heart”. Casa Milà, better known as La Pedrera, is a building designed by the Catalan architect Antoni Gaudí and built during the years 1905–1910, being considered officially completed in 1912. It is located at 92, Passeig de Gràcia in the Eixample district of Barcelona, Catalonia, Spain. (Photo by Stefano Scarselli)