A bird is cleaned at the International Bird Rescue in Fairfield, California January 20, 2015. A gooey, unknown material discovered on the eastern shores of San Francisco Bay is clinging to the feathers of birds, and more than 100 birds, mostly species of oceangoing, diving ducks, have died after their feathers were fouled by the viscous substance now undergoing testing at state labs in Sacramento. (Photo by Robert Galbraith/Reuters)

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)

A student uses a ruler to measure the distance between forks before a formal dinner at The International Butler Academy China on September 16, 2014 in Chengdu, China. Over the last several years, there has been a surge in demand among China's wealthy for Western-trained butlers, with many academies seeing large portions of their graduating classes hired by Chinese families or companies. (Photo by Taylor Weidman/Getty Images)

A model poses beside a Mazda MX-5 during a media presentation at the 37th Bangkok International Motor Show in Bangkok, Thailand, March 22, 2016. (Photo by Chaiwat Subprasom/Reuters)

German KUKA Robotics' robot LBR iiwa demonstrates a flower arrangement at the International Robot exhibition in Tokyo, Wednesday, December 2, 2015. (Photo by Shizuo Kambayashi/AP Photo)

The Pioneer Team, a civil aerobatic team from Italy, let off pyrotechnics from their Pioneer 330 aircraft during the Malta International Airshow off SmartCity Malta, outside Valletta, Malta, September 24, 2016. (Photo by Darrin Zammit Lupi/Reuters)

Cake made by Gisela Prekau on display at the Cake International show at Alexandra Palace in London, UK on April 22, 2017. Cake International 2017, the Cake Decorating and Baking Show, takes place over the weekend at Alexandra Palace, North London featuring giant cakes, moving cakes, stunning crafter cakes, exquisitely detailed cakes and the latest ranges of cake decorating products and accessories, college displays and workshops. (Photo by Dinendra Haria/Rex Features/Shutterstock)

This photo taken on June 19, 2017 shows Indian yoga teacher Mahesh Yogiji attempting a world record for the longest yoga session in Ahmedabad, ahead of International Yoga Day on June 21. According to Guiness World Records, the longest yoga marathon undertaken by a man lasted 69 hours and was achieved by V Gunasekaran in Tamil Nadu in June 2016. (Photo by Sam Panthaky/AFP Photo)