“Slow”. A calm cow in the messy streets of Jodhpur. Photo location: India. (Photo and caption by Matthias Troeger/National Geographic Photo Contest)

A woman rides the world's longest urban zip line, with a speed of up to 80 kilometers per hour on a one kilometer run from 170 meter to ground level, in the Marina district of Dubai, United Arab Emirates, Tuesday, December 5, 2017. (Photo by Kamran Jebreili/AP Photo)

Mabel attends The BRIT Awards 2018 nominations photocall held at ITV Studios on January 13, 2018 in London, England. (Photo by Nils Jorgensen/Rex Features/Shutterstock)

Model Emily Ratajkowski attends the “Loveless (Nelyubov)” screening during the 70th annual Cannes Film Festival at Palais des Festivals on May 18, 2017 in Cannes, France. (Photo by Stephane Mahe/Reuters)

Jury member Nicole Kidman attends the Jury Press Conference. (Photo by Vittorio Zunino Celotto/Getty Images)

A pile of destroyed cars of teachers sits outside Briarwood elementary school in Oklahoma City, Oklahoma May 22, 2013. Rescue workers with sniffer dogs picked through the ruins on Wednesday to ensure no survivors remained buried after a deadly tornado left thousands homeless and trying to salvage what was left of their belongings. Curvature of horizon in the photo is due to an ultra-wide angle lens. (Photo by Rick Wilking/Reuters)

Actor George Clooney from the film “Ides Of March” arrives at the Hotel Excelsior during the 68th Venice Film Festival on August 31, 2011 in Venice, Italy. (Photo by Gareth Cattermole/Getty Images)

Laura Halford of Wales jumps during her hoop routine as she competes in the rhythmic gymnastics individual all-around final event at the 2014 Commonwealth Games in Glasgow, Scotland, July 25, 2014. (Photo by Phil Noble/Reuters)