Team Strong Silvers member Ngai Hin Kwok, 66, works out as teammate Ng Siu Chi, 57, watches at a stadium in Singapore March 15, 2015. Team Strong Silvers, is a group of senior citizens who train in calisthenics. The trio trains individually at least three times a week, and meets up for joint calisthenics at least twice a month. (Photo by Edgar Su/Reuters)

Children play amid icebergs on the beach in Nuuk, Greenland, June 5, 2016. (Photo by Alister Doyle/Reuters)

Soldiers take part in a drill during a heavy snow in Heihe, Heilongjiang province, February 26, 2014. (Photo by Reuters/China Daily)

A Polisario fighter sits on a rock at a forward base on the outskirts of Tifariti, Western Sahara, September 9, 2016. At a rocky outpost in Western Sahara, a new generation of soldiers who have never known war are mobilising as tensions resurface in one of Africa's oldest disputes after a quarter century of uneasy peace. (Photo by Zohra Bensemra/Reuters)

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)

One of the poor families collecting firewood from the street and the burn to feel some warmth in Aleppo, Syria on August 19, 2016. (Photo by Basem Ayoubi/Imageslive/ZUMA Press/Splash News)

A reveller smeared in vermilion powder celebrates the Bisket Jatra Festival in Thimi in the Bhaktapur District on the outskirts of Kathmandu on April 15, 2023. (Photo by Prakash Mathema/AFP Photo)

People gather to view a new art installaiton at Waterfront Park entitled, Interstellar Influencer (Make an Impact) by Jason Klimoski and Lesley Chang of STUDIOKCA on Saturday March 30, 2024 in Alexandria, VA. The artwork depicts an asteroid that struck the region millions of years ago. (Photo by Matt McClain/The Washington Post)