A visitor walks on a giant chalk artwork called “Wasting Time” at the Chalk Urban Arts Festival in Sydney on October 25, 2014. The picture is the biggest 3-D artwork created in Australia by two artists, Leon Keer from Holland and Jenny McCracken from Australia. (Photo by Peter Parks/AFP Photo)

“Red Land: Sunset Cloud Village is one of the most picturesque places in Red Land, China. As its name indicates, it's best to see before sunset. The reddish brown soil turns redder after rainfall and after farmers plow the land”. (Photo and comment by Peng Jiang/National Geographic Photo Contest via The Atlantic)

Yakelin Hernandez, 18, poses for a photograph near The Malecon where The Carnival was held, on August 14, 2015. Colorful costumes, dancing, parades and street parties on the Malecon in Havana, Cuba are all part of Havana Carnival 2015 which was held in August. (Photo by Sarah L. Voisin/The Washington Post)

A participant prepares for the Red Bull Air Race World Championships in Abu Dhabi, United Arab Emirates on February 6, 2017. (Photo by Red Bull Content Pool/SIPA Press/Rex Features/Shutterstock)

A young woman wearing no trousers hits the ski slopes at a ski resort in Xuzhou, in east China's Jiangsu province on January 13, 2015 in a promotional effort to equal “No Pants Subway Ride”, which was marked on January 11 this year. The promotional “No Pants Subway Ride” stunt on January 11 was held as commuters in some 60 cities around the world braved public transportation in their undies, which has gone global since its first staging by US group Improv Everywhere in New York in 2002. (Photo by AFP Photo)

A woman smokes a mask bong on the final day of Hempfest, Seattle's annual gathering to promote the legalization of marijuana, on August 17, 2014. (Photo by Jordan Stead/Seattlepi.com)

Mario Huettenhofer, chief of the German company 3D Fab, presents his own face as 3d print during the international fairs FabCon 3.D and Rapid.Tech in Erfurt, Germany, Thursday, May 15, 2014. 130 exhibitors from all over the world present the entire world of 3D printing. The trade fairs are accompanied by specialist programs featuring 80 scientists, practitioners and trend analysts from ten countries, who will explain the latest findings, trends and applications for additive processes in industry and for 3D printing in the private sector to newcomers, experts and consumers alike. (Photo by Jens Meyer/AP Photo)