Young people fight for fun with their pillows, during the International Pillow Fight Day at the Place des Grottes, in Geneva, Switzerland, Saturday, April 4, 2015. The annual International Pillow Fight Day takes place in hundreds of cities around the world. (Photo by Salvatore Di Nolfi/AP Photo/Keystone)

Ada Wood, 10, perches on one of Castlerigg’s 38 stones during the summer solstice at Castlerigg stone circle in Cumbria, Britain, on June 21, 2016. (Photo by Christopher Thomond/The Guardian)

A sniper of the French “Brigade d'Intervention” takes up his position at the top of the Arc de Triomphe during the annual Bastille Day military parade on the Champs-Elysees avenue in Paris on July 14, 2016. France holds annual Bastille Day military parade with troops from Australia and New Zealand as special guests among the 3,000 soldiers who will march up the Champs Elysees avenue. They will be accompanied by 200 vehicles with 85 aircraft flying overhead. (Photo by Stephane De Sakutin/AFP Photo)

Alessandra Perilli, of San Marino, competes during the trap women's qualification at the 2016 Summer Olympics in Rio de Janeiro, Brazil, Sunday, August 7, 2016. (Photo by Hassan Ammar/AP Photo)

Samba dancers arrive to perform ahead of the athletics competitions of the 2016 Summer Olympics at the Olympic stadium in Rio de Janeiro, Brazil, Sunday, August 14, 2016. (Photo by Jae C. Hong/AP Photo)

A man wearing a Pikachu hat, a character from Pokemon, plays Pokemon Go during a gathering to celebrate “Pokemon Day” in Mexico City, Mexico August 21, 2016. (Photo by Carlos Jasso/Reuters)

Four men dressed as zombies participate in a Zombie Walk procession in the streets of Paris October 12, 2013. (Photo by Benoit Tessier/Reuters)

Elephants enjoy various kinds of fruits and vegetables during an all-you-can-eat elephant buffet held to mark the National Elephant Day at the ancient historical city of Ayutthaya, Thailand, 13 March 2014. The annual National Thai Elephant Day is held on 13 March to celebrate and drawing public attention for more concerted effort to save the species and protect its habitat. Thailand sees a severe decline with less than 3,000 wild elephants left in the kingdom. (Photo by Rungroj Yongrit/EPA)