Mud-covered tourists pretend to be trapped inside a mud prison at the Daecheon Beach Mud Plaza in the city of Boryeong on South Korea's west coast, July 17, as they take part in the Boryeong Mud Festival, which opened that day and runs through July 26. Boryeong mud is rich in natural mineral component and is considered to prevent skin aging. (Photo by EPA/Yonhap)

Lindsay Knutson plays in the heavy snow with her family dog, Aspen, and daughter Flora Bejblik, 4, cq, as her husband Bob Bejblik, rear left, shovels, Tuesday, March 5, 2013 in southwest Minneapolis. The National Weather Service predicted a two-day snow total of 8 to 12 inches for much of southeastern and east-central Minnesota, including the Twin Cities. (Photo by Elizabeth Flores/AP Photo/The Star Tribune)

Marek Jama performs during the gala of the 41 st Monte- Carlo International Circus Festival in Monaco on January 25, 2017. (Photo by Eric Gaillard/AFP Photo)

People are seen watching hot air balloons fly overhead during a two-day international hot air balloon festival in Eshkol Park near the southern city of Netivot, Israel July 22, 2016. (Photo by Amir Cohen/Reuters)

Humanoid robot bartender “Carl” interacts with guests at the Robots Bar and Lounge in the eastern German town of Ilmenau, July 26, 2013. “Carl”, developed and built by mechatronics engineer Ben Schaefer who runs a company for humanoid robots, prepares spirits for the mixing of cocktails and is able to interact with customers in small conversations. (Photo by Fabrizio Bensch/Reuters)

Kevin and Merith Starren have their picture taken by Merith's brother Mark Ernst (R) and nephew Logan Ernst (L) in front of a 50-foot snowman named “Granddaddy” in Gilman, Minnesota, March 6, 2014. (Photo by Eric Miller/Reuters)

Men wear masks as they sit in the metro in Prague, Czech Republic, 17 March 2020. According to media reports, the Czech government decided to impose a two-week quarantine in the country on the evening of 15 March, and ban all international travel from 16 March 2020. Currently 383 cases of the coronavirus SARS-CoV-2, which causes the Covid-19 disease, have been officially confirmed in Czech Republic. (Photo by Martin Divisek/EPA/EFE)