Winner of the National Park Foundation's photo contest; Honorable Mention: Fan Favorite. Grand Canyon National Park, Arizona. Three friends enjoy sunrise over the Grand Canyon. (Photo by Peter Blanchard)

Alisa, 10, gets a kiss from one of the wolves her family tamed in the village of Zacherevye, Belarus, on August 17, 2014. (Photo by Sergei Gapon/AFP Photo)

Dancers at the Windmill Theatre in London, England practice a routine wearing gas masks and hard-hats with their costumes, 1940. (Photo by Hulton Archive/Getty Images)

Andrey Karr from Western Riders Slacklines at sunset above big waves in Nazare, Portugal on December 27, 2017. (Photo by Aidan Williams/National Geographic Travel Photographer of the Year Contest)

In the mountains of central Vietnam, a colossal pair of hands lifts a golden thread of walkway high above the clifftops, as if the mountain itself has sprouted limbs. Here: A giant hand structure at the Gold Bridge is seen on Ba Na hill near Danang city, Vietnam on August 1, 2018. (Photo by Reuters/Kham)

Leon Samson, 24-year-old showman, grimaces as an automobile is driven across his chest at Perth, Australia on October 9, 1960. Samson said the towel on his chest is to prevent the wheel from tearing his flesh. (Photo by AP Photo)

A visitor takes pictures with a smartphone of an artwork entitled “Blue Europe, 2015” by Chinese artist Liu Bolin, on display during the exhibition “Visible Invisible” at the Mudec Museum in Milan on May 14, 2019. Liu Bolin known as “the invisible man” for his photographic self-portraits, focused on a body-painting blending with the surrounding area. (Photo by Miguel Medina/AFP Photo)

A leather worker with his frightening types of clothes prepares after painted themselves using chimney soot as they participate in a programme within the September 6 celebrations, in Balikesir, Turkey on September 06, 2019. According to the story, “Tulutabaklar” were painting themselves with ash and wearing goatskin or sheep skin to frighten the Greek soldiers occupying Balikesir during the National Struggle period. Every year on September 6, Tulutabaklar perform this ritual as part of the celebration of liberation of the city for 96 years. (Photo by Ali Atmaca/Anadolu Agency via Getty Images)