These two young siblings appear to cling on to a tree for dear life and even hold hands as they learn the ropes of climbing, on June 25, 2013. (Photo by Tim Fitzharris/Minden/Solent)

A labourer pulls a cart loaded with sacks of spices at a wholesale spice and chemical market in the old quarters of Delhi, India, December 19, 2016. Picture taken December 19, 2016. (Photo by Adnan Abidi/Reuters)

Civil security aircrafts parade during the inauguration of the Nimes-Garons civil security air force base on March 10, 2017 in Nimes, southern France. (Photo by Pascal Guyot/AFP Photo)

A wolverine is pictured during its first public appearance at the Animal Park of Sainte-Croix in Rhodes, eastern France on January 28, 2016. (Photo by Frederick Florin/AFP Photo)

People take cover outside the Fort Lauderdale-Hollywood International airport after a shooting took place near the baggage claim on January 6, 2017 in Fort Lauderdale, Florida. Officials are reporting that five people were killed and 8 wounded in an attack by a single gunman. (Photo by Joe Raedle/Getty Images)

A Chinese shopper sleeps on a bed in the showroom of the IKEA store on July 6, 2014 in Beijing, China. Of the world's ten biggest Ikea stores, 8 of them are in China to cater to the country's growing middle class. The stores are designed with extra room displays given the tendency for customers to make a visit an all-day affair. Store management does not discourage shoppers from sleeping on Ikea furniture, even marking them with signs inviting customers to try them out. (Photo by Kevin Frayer/Getty Images)

A Poison Ivy and Boba Fet (Star Wars) cosplayer during the MCM Birmingham Comic Con at NEC Arena on March 18, 2017 in Birmingham, England. (Photo by Ollie Millington/Getty Images)

“Strike Through The Mothership”. Every May for the last 3 years I have driven down to Tornado Alley to capture some amazing storms. This supercell held so much promise to drop a tornado but one small shift in the atmosphere and all that it produced was an extreme lightning show. Photo location: Broken Bow, Nebraska. (Photo and caption by Vanessa Neufeld/National Geographic Photo Contest)