Riot police clash with demonstrators protesting against proposed pension reforms outside the Congress in Buenos Aires on December 18, 2017. Protesters angry at proposed pension and welfare reforms attacked police close to Argentina's congress building in Buenos Aires on Monday, the second protest in a week to turn violent. Activists lobbed stones, bottles and firecrackers at police as huge crowds demonstrated against pension reforms proposed by the center-right government of President Mauricio Macri. (Photo by Eitan Abramovich/AFP Photo)

An air raid drill at Seattle College caught students William Bates, left, and Edna Mae Farrell, right, while they were eating their lunch in the school café, but they simply took shelter under the table and continued eating in Seattle, Washington, March 17, 1942. Air raid wardens said 350 students left their classrooms and assembled in shelters within one minute in first at the college. (Photo by AP Photo)

Syrian rescue workers and residents help an injured woman following a reported air strike by government forces on the rebel-held neighbourhood of Haydariya in the northern city of Aleppo on April 10, 2016. (Photo by Thaer Mohammed/AFP Photo)

Crew members work to secure a hot air balloon after landing during the 2015 Albuquerque International Balloon Fiesta in Albuquerque, New Mexico, October 4, 2015. (Photo by Lucas Jackson/Reuters)

The Peugeot vehicle of driver Carlos Sainz of Spain is seen at the technical verification area ahead of the Dakar Rally 2016 in Buenos Aires, Argentina, January 1, 2016. (Photo by Marcos Brindicci/Reuters)

Two biplanes of the Team Breitling cross during a training flight prior the AIR14 air show in Payerne, Switzerland, August 29, 2014. (Photo by Peter Schneider/EPA)

Mount Sinabung continues to spew thick smoke into the air in Karo, North Sumatra on October 30, 2020. (Photo by Albert Ivan Damanik/Anadolu Agency via Getty Images)

Men soar through the air on a wooden sledge during a traditional Bavarian horn sledge race, known as “Schnablerrennen”, in Gaissach near Bad Toelz, Germany, January 22, 2017. (Photo by Michael Dalder/Reuters)