Ride operator Van Mai wears a face mask against the spread of the coronavirus while working at the Playland amusement park at the Pacific National Exhibition, in Vancouver, British Columbia, Friday, July 10, 2020. (Photo by Darryl Dyck/The Canadian Press via AP Photo)

U.S. Marines, left, and South Korean Marines, wearing blue headbands on their helmets, take positions after landing on the beach during the joint military combined amphibious exercise, called Ssangyong, part of the Key Resolve and Foal Eagle military exercises, in Pohang, South Korea, Saturday, March 12, 2016. North Korea said Saturday its military is ready to pre-emptively attack and “liberate” the South in its latest outburst against the annual joint military drills by the United States and South Korea. (Photo by Kim Jun-bum/Yonhap via AP Photo)

Hotel staff practice self-defence skills after a training session given by team member of Special Weapons and Tactics (SWAT) team, in Hangzhou, Zhejiang province, April 7, 2016. (Photo by Reuters/Stringer)

An internally displaced woman collects water from a pond to construct a mud-house at the Aboushok camp in El Fasher, North Darfur, Sudan, November 17, 2015. The conflict in Sudan's Darfur region that erupted 12 years ago shows no sign of ending. But it hasn't stopped displaced youngsters, some of whom have spent their entire lives in refugee camps, from dreaming big. Twelve children aged 12 explain their hopes and dreams for the future; ambitions include becoming a doctor, an engineer and a teacher. (Photo by Mohamed Nureldin Abdallah/Reuters)

Street vendosr prepare grilled pigs to sell for the Chinese New Year celebrations at a market in Phnom Penh, Cambodia, 11 February 2021. Chinese people around the world celebrate the Lunar New Year, also known as the Spring Festival, which marks the year of the Ox. (Photo by Kith Serey/EPA/EFE)

A U.S. Army B-24 Liberator Bomber is hailed by a ground crewman as it takes off over a line of shark- nosed fighter planes at an advanced base in China on a mission on October 10, 1943, to bomb Japanese installations. (Photo by AP Photo)

A dancer performs during the Gymnastics Rio Gala on Day 12 of the 2016 Rio Olympic Games on August 17, 2016 in Rio de Janeiro, Brazil. (Photo by Clive Brunskill/Getty Images)

A general view of the Cathedral on the Blood on November 2, 2011 in Yekaterinburg, Russia. Yekaterinburg is one of thirteen cities proposed as a host city for 2018 FIFA World Cup in Russia. (Photo by Harry Engels/Getty Images)