Children play at a makeshift camp for migrants and refugees at the Greek-Macedonian border near the village of Idomeni, Greece, March 29, 2016. (Photo by Marko Djurica/Reuters)

Anti-pollution protesters wearing traditional costumes and contemporary gas masks ride bicycles in the Qingming Grand river park in Kaifeng, Henan Province, China on January 1, 2017. The Beijing Municipal Environmental Protection Bureau extended an “orange alert” for heavy air pollution for three more days. (Photo by SIPA Asia/Rex Features/Shutterstock)

Alejandro Ccasa prays after waiting three days next to an empty oxygen tank for his uncle who has COVID-19 outside a refill shop where he is the first in line before it opens in Callao, Peru, early Tuesday, February 2, 2021. Ccasa said his family has one large tank and it gives about four hours of oxygen therapy. (Photo by Martin Mejia/AP Photo)

A visiitor bungee jumps during an outdoor festival to celebrate German Unity Day on the 21st anniversary of German reunification on October 3, 2011 in Berlin, Germany. German Unity Day is a national holiday and marks the day West Germany and East Germany were reunited in 1990 following the collapse of the Iron Curtain. (Photo by Adam Berry/Getty Images)

A migrant smokes a cigarette as he waits among others to cross the Croatian border near the village of Berkasovo, Serbia October 19, 2015. Thousands of migrants clamoured to enter European Union member Croatia from Serbia on Monday after a night spent in the cold and mud of no-man's land, their passage west slowed by a Slovenian effort to impose limits on the flow to western Europe. (Photo by Marko Djurica/Reuters)

A sculpture entitled “Powerless Structures, Fig.101” designed by Danish artist Michael Elmgreen and Norwegian artist Ingar Dragset is unveiled on the Fourth Plinth in Trafalgar Square on February 23, 2012 in London, England. (Photo by Oli Scarff/Getty Images)

Russian cosmonaut Alexander Skvortsov, Expedition 40 flight engineer, attired in a Russian Orlan spacesuit, participates in a session of extravehicular activity (EVA) in support of science and maintenance on the International Space Station on August 18, 2014. During the five-hour, 11-minute spacewalk, Skvortsov and cosmonaut Oleg Artemyev (out of frame) deployed a small science satellite, retrieved and installed experiment packages and inspected components on the exterior of the orbital laboratory. (Photo by NASA)

Train attendants attend an etiquette trainning as the May Day holiday approaches on April 26, 2022 in Chongqing, China. (Photo by Su Zhigang/VCG via Getty Images)