Students training to be flight attendants hold books on their heads, chopsticks in their mouths, and papers in between their knees, as they take part in a standing posture practice at a vocational school in Shijiazhuang, Hebei province, China May 4, 2017. (Photo by Reuters/Stringer)

“The Challenge!” Young boy relishes in a game of tug of war before school. Photo location: Lake Titicaca, Peru. (Photo and caption by Paul Heyman/National Geographic Photo Contest)

Model Miranda Kerr attends the after party for the 2012 Victoria's Secret Fashion Show at Lavo NYC on November 7, 2012 in New York City. (Photo by Jim Spellman/WireImage)

Meghan Puhr participates in a virtual realty presentation during an Intel news conference before CES International, Wednesday, January 4, 2017, in Las Vegas. (Photo by John Locher/AP Photo)

A man carrying butchered dogs drives past a pet dog at a dog meat market in Yulin, Guangxi Autonomous Region, June 21, 2015. (Photo by Kim Kyung-Hoon/Reuters)

Francisco Solano poses for a photo in his bird-feather suit after attending a Mass commemorating the feast day of St. Francis Solano, in Emboscada, Paraguay, Friday, July 24, 2015. Some 500 people attended the festivity – a mix of indigenous and Guarani Indian beliefs. The festival begins with a Mass, continues with a procession of the diminutive wooden statue of St. Francis, and ends with people dancing in suits made with black, white, brown and grey feathers. (Photo by Jorge Saenz/AP Photo)

Plants grow on houses in the abandoned fishing village of Houtouwan on the island of Shengshan July 26, 2015. Just a handful of people still live in a village on Shengshan Island east of Shanghai that was once home to more than 2,000 fishermen. Every day hundreds of tourists visit Houtouwan, making their way on narrow footpaths past tumbledown houses overtaken by vegetation. The remote village, on one of more than 400 islands in the Shengsi archipelago, was abandoned in the early 1990s as first wealthy residents then others moved away, aiming to leave problems with education and food delivery behind them. (Photo by Damir Sagolj/Reuters)

Developed for the British American Ambulance Corps, this new motorcycle ambulance is capable of speeding wounded soldiers 90 miles an hour from the front lines to field hospitals. Its springs are synchronized with the patient's heartbeat to avoid increasing fever when traveling over various Terrain. Viewing it in New York August 27, 1941, are left to right: constable Herbert Scott of England, driver; William E. Detlor, whose firm developed the vehicle; M. W. Stand, inspector-general of Civilian Defense, and Maj. Edward Riekert, also. (Photo by AP Photo)