Russian servicemen look on as a Mi-24 helicopter fly overhead during the Open Water competition for pontoon bridge units, as part of the International Army Games 2018, outside Murom, Russia August 3, 2018. (Photo by Maxim Shemetov/Reuters)

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 customer grimaces in pain as she gets a tattoo on her arm at the 21st International Tattoo Convention Berlin on December 3, 2011 in Berlin, Germany. The annual tattoo trade fair runs from December 2–4, 2011. (Photo by Adam Berry/Getty Images)

Tattoo artists and body art fans from across the globe have descended on London for one of the biggest and most prestigious tattoo conventions. “This is like the Premier League of tattoo artists from all over the world who come here to show their work”, organiser Marcus Beriman said. Photo: Bugz Bonniie displays some of her tattoos. (Photo by Oli Scarff)

Robert Price of TREWGrip LLC demonstrates a TREWGrip handheld rear-type keyboard and air mouse for Apple and Android tablets at the “CES: Unveiled”, media preview for International CES, at the Mandalay Bay Convention Center in Las Vegas on January 5, 2014. (Photo by Robyn Beck/AFP Photo)

A woman counts her money as she sells flowers ahead of International Women's Day in central Kiev, Ukraine on March 7, 2019. (Photo by Gleb Garanich/Reuters)