People stand along Aviation Blvd. as the space shuttle Endeavour lands at LAX in Los Angeles. (Photo by Wally Skalij/Los Angeles Times/MCT)

An incredible clear-air lightning display from storms to the east of Noonamah, just outside Darwin on April 6, 2015. (Photo by Jacci Ingham/The Guardian)

A boat sails behind a woman looking through binoculars as she sits on a cliff on a sunny day in Sydney, Australia, May 29, 2016. (Photo by David Gray/Reuters)

Fans dressed in Spider-Man outfits gather at a promotional event for the forthcoming “Spider-Man: Homecoming” movie at the Art Science Museum in Singapore on June 7, 2017. The movie will be shown in cinemas around the world from July 5 onwards. (Photo by Toh Ting Wei/AFP Photo)

“Kids of Sapa”. Four little beautiful Hmong girls from Lao Chai Village, near Sapa, Vietnam. (Photo and caption by Felipe Hanower/National Geographic Traveler Photo Contest)

Bikini-clad women ski as they are led by a car during a performance on the frozen Yenisei River outside Krasnoyarsk, Siberia, Russia, March 20, 2016. The performance, entitled “Siberian Spring's Strings” and created with the participation of artist Vasily Slonov, marked the day of spring equinox (vernal equinox), according to organizers. (Photo by Ilya Naymushin/Reuters)

A woman carries a piglet as she runs on ice during a running challenge in Changsha, Hunan province February 8, 2015. A total of 20 people participated in the challenge requiring them to choose a pig ranging between 15 kg and 115 kg in weight, and carrying it while running on a 20.15-metre-long ice track. The participants that complete the challenge will be rewarded with the pig they carried, local media reported. (Photo by Darwin Zhou/Reuters)

Spacewalker Mark Vande Hei took his own photograph during the first spacewalk of 2018, on January 23, 2018. These sky-high pictures are better known as “space-selfies”. (Photo by Mark Vande Hei/NASA)