School teachers and staff members take part during an active shooter training at James I. O'Neill High School in Highland Falls, New York, U.S., December 12, 2017. (Photo by Eduardo Munoz/Reuters)

A woman laughs as she takes part in the “Domingo Fareleiro” (Floury Sunday in Galician) festival in the village of Xinzo de Limia, northwestern Spain, on January 21, 2018. Domingo Fareleiro (Floury Sunday) takes place annually in Xinzo de Limia, Spain, in a unique celebration that gives the starting signal for a long festive period known as Entroido, or Carnival. (Photo by Miguel Riopa/AFP Photo)

Women take part in an annual block party known as “Banda do Candinho e Mulatas” (Candinho Band and Mulatto Women), during carnival festivities at Bixiga neighbourhood in Sao Paulo, Brazil February 7, 2018. (Photo by Nacho Doce/Reuters)

Competitors stretch before taking part in day three of the World Irish Dancing Championships on March 26, 2018 in Glasgow, Scotland. The World Irish Dancing Championships are taking place in Glasgow this week at the Royal Concert Hall, with more than 14,500 dancers and supporters expected to travel to the championships which has run for more than forty years. (Photo by Jeff J. Mitchell/Getty Images)

“Aurora Hunters”. Photographers taking part in a photography tour on the Lofoten Islands in Norway, pull over on the side of the road to take a photo of their first ever Aurora Borealis after spotting it from their tour bus. Photo location: Rystad, Lofoten Islands, Norway. (Photo and caption by Mark Gee/National Geographic Photo Contest)

Danny Santos started photography as a hobby a few years ago, shooting strangers in the streets of Singapore every weekends. He still does that from time to time. Now he juggles between his day job as a graphic designer, and his part-time work as a freelance photographer. (Photo by Danny Santos)

Chinese women holding toy guns dance for a revolutionary song during their daily exercise at a square outside a shopping mall in Beijing, June 29, 2014. About 30 local residents formed this “Nanguan” art group that enjoys performing to revolutionary songs and dance performances as part of their daily fitness activities at night. (Photo by Jason Lee/Reuters)

In this handout artists impression provided by the Russia 2018 Organising Commitee, the Rostov on Don Stadium is shown as proposed and presented as part of the Russia 2018 World Cup bid, on September 29, 2011 in Russia. (Illustration by Russia 2018 via Getty Images)