Members of the Wasteland Warriors from the movie “MadMax” pose during the Wacken Open Air festival on August 4, 2016 in Wacken, Germany. Wacken is a village in northern Germany with a population of 1,800 that has hosted the annual festival, which attracts heavy metal fans from around the world, since 1990. (Photo by Alexander Koerner/Getty Images)

The sky looked on fire this morning, as it made the clouds glow red, just before sunrise at Peterborough Rowing Lake, in Nene Park, UK on January 18, 2017. (Photo by Paul Marriott/Rex Features/Shutterstock)

A photographer takes a snapshot of the reflection of balloons as they take off from Balloon fiesta park in Corrales, N.M., near a north diversion channel reservoir Wednesday, October 7, 2015. (Photo by Roberto E. Rosales/Albuquerque Journal via AP Photo)

An Egyptian security guard screams at people as medics bring in a stretcher to carry the wounded after the attack which killed President Anwar Sadat, October 6, 1981, as he watched a military parade. (Photo by AP Photo)

The fourth annual BigPicture Natural World Photography Competition aims to celebrate the diversity of life on Earth, and encourages people to protect and conserve it. Here: “The Salmon Catchers”. Terrestrial Wildlife. To capture this view of a mother grizzly bear and her cub, photographer Peter Mather set up a camera trap on a log that he knew the bears tended to traverse while fishing for salmon, in the Yukon River watershed in Canada. (Photo by Peter Mather/BigPicture Natural World Photography Competition 2017)

Participants of the 77th edition of the annual Christmas swimming 'Coupe de Noel' jump into the waters of Lake Geneva, in Geneva, Switzerland, 20 December 2015. More than 1,540 men and women braved the water temperature of just 8 degrees Celsius as they swam a 120 meters distance at the traditional Christmas swimming in Geneva. (Photo by Salvatore Di Nolfi/EPA)

“Double head vulture”. On the day of windy days during raptors migration some people in my country start to catch these tired raptors, so in this day we go to photograph some raptors and we saw these tow tired vultures, so we start to drag them away from the hunters until they reach a good hidden place, to make them safe until they start a new journey. Photo location: Kuwait. (Photo and caption by Mohd Khorshed/National Geographic Photo Contest)

Naki'o, a mixed-breed dog with four prosthetic devices, goes for a run in Colorado Springs April 12, 2013. Naki'o lost all four feet to frostbite when he was abandoned as a puppy in a foreclosed home. (Photo by Rick Wilking/Reuters)