Friends pose for a picture on a night out in Leeds, United Kingdom after receiving their A Level results on Tuesday, August 10, 2021. Students hit the town across the country, downing cocktails and letting their hair down after two years of studying during the pandemic. (Photo by Nb press ltd)

People wear face masks while watching the marine life at Ripley's Aquarium of Canada during the COVID-19 pandemic in Toronto, on Wednesday, October 28, 2020. (Photo by Nathan Denette/The Canadian Press via AP Photo)

Border guard officers, wearing masks against COVID-19 infection adjust their outfits before a distinguished service awards ceremony for employees of the interior ministry in Bucharest, Romania, Thursday, July 16, 2020. Romania has registered on Thursday the highest number of COVID-19 infection cases since the pandemic reached the country in February, 777 in a 24 hours interval, as many fail to observe the mandatory protection measures, like the use of a face mask indoors or maintaining social distancing. (Photo by Andreea Alexandru/AP Photo)

Participants climb over a wall at the “Tough Mudder” endurance event series in Arnsberg September 6, 2014. Competitors who took part in the endurance event saw themselves having to overcome various military style obstacles. (Photo by Ina Fassbender/Reuters)

A member of the “Exit Point” amateur rope-jumping group jumps from a 44-metre high (144-feet high) waterpipe bridge in the Siberian Taiga area outside Krasnoyarsk, September 28, 2014. Fans of rope-jumping, a kind of extreme sport involving a jump from a high point using an advanced system of amortization including mountaineering and rope safety equipment, attended the Golden Autumn group's jumping season. (Photo by Ilya Naymushin/Reuters)

Animal rights activists covered with fake blood sit on the floor during a protest against the use of animals in research to mark World Day for Animals in Laboratories in central Madrid April 24, 2014. The sign reads, “How many rabbits do your shampoo kill?”. (Photo by Andrea Comas/Reuters)

People walk through crop circles in a cornfield near Raisting, Germany, on July 28, 2014. According to media reports, a balloonist had discovered the circle some days ago. Since then, hundreds of people came to the field to watch it, however it is unclear who did create the pattern. (Photo by Karl-Josef Hildenbrand/DPA)

In this undated photo made available by journal Nature on January 15, 2014, a northern bald ibis (Geronticus eremita) flies in Tuscany, Italy. A new study released Wednesday, January 15, 2014 says the birds choreograph the flapping of their wings, getting a boost from an updraft of air in the wake of the flapping wings by flying behind the first bird and off to the side. When a flock of birds take advantage of these aerodynamics, they form a V. (Photo by Markus Unsöld/AP Photo)