A picturesque supercell formation in the northwest of Booker, Texas from June 2013. (Photo by Mike Olbinski/Barcroft Media)

Visitors view ice sculptures at the 29th Harbin International Ice and Snow Festival on January 5, 2013. (Photo by Associated Press)

A woman struggles with an umbrella in the wind and rain while walking in Derby city centre, on December 23, 2013. (Photo by Rui Vieira/PA Wire)

Gorillas at Royal Burgers’ Zoo, Arnhem, Netherlands, on November 28, 2013. (Photo by Vidi Photo/Startraks Photo New York)

Contestant of the Muslimah World 2013, Obabiyi Aishah Ajibola (C) of Nigeria, is reflected in a mirror checking her make-up while contestants wait for a grand final during the Muslimah World competition in Jakarta on September 18, 2013. (Photo by Adek Berry/AFP Photo)

Employees of a food stand take pictures of Titan, a robot created by England Cyberstein Robots, performing at the Danilovsly market in downtown of Moscow, Russia, 12 May 2014. Titan visited to Moscow to attend “Bal Robotov”, an interactive exhibition of the most recent advances in robotics which will be opened on 15 May in Artplay Moscow exhibition center. Titan worked alongside superstars including Will.i.am, Rihanna, Will Smith and Jackie Chan. (Photo by Sergei Ilnitsky/EPA)

Labourers who work nearby nap on a road as cars drive past in Chongqing Municipality, July 23, 2013. (Photo by Reuters/Stringer)