Gunfire was brought to the steps of President Truman's Washington home, Blair House, as two assassins tried to kill the chief executive, November 1, 1950. One of the gunmen, Oscar Collazzo of New York, lay wounded at the bottom of Blair House's front steps after the president's police guard had finished their work, at the cost of one guards' life, Dec. 9, 1950. The second gunman was killed. (Photo by Harvey Georges/AP Photo)

Long row of shiny new Flying Fortresses, part of huge reserves being built up in Britain for D-Day, stands by to be flown to combat units as replacements, May 25, 1944. (Photo by AP Photo)

The Northern Lights glow green in a spectacular light show above a field of trees frozen solid with snow. (Photo by Jaak Sarv/Solent News & Photo Agency)

A dead body is seen on the ground after violence erupted in the Independence Square in Kiev February 20, 2014. Ukrainian protesters seized back Kiev's Independence Square in fresh clashes with riot police on Thursday that left several injured and possibly two demonstrators dead. (Photo by David Mdzinarishvili/Reuters)

Frost covers a face shield of a volunteer before the start of the women's 7.5km + 7.5km skiathlon cross-country skiing competition at the 2022 Winter Olympics, Saturday, February 5, 2022, in Zhangjiakou, China. (Photo by Alessandra Tarantino/AP Photo)

Itzhak de Laat of Team Netherlands crashes during the Men's 500m Heats on day seven of the Beijing 2022 Winter Olympic Games at Capital Indoor Stadium on February 11, 2022 in Beijing, China. (Photo by Toby Melville/Reuters)

A participant learns to throw a grenade during a military exercise for civilians conducted by members of the Georgian National Legion paramilitary volunteer unit amid threat of Russian invasion in Kyiv, Ukraine on February 4, 2022. (Photo by Serhii Nuzhnenko/Reuters)

Paul Poirier of Canada and Marjorie Lajoie of Canada after training before the Figure Skating Ice Dance – Rhythm Dance at Capital Indoor Stadium in Beijing, China on February 12, 2022. (Photo by Aleksandra Szmigiel/Reuters)