Recruits who earned a place in the Motivation Platoon struggle through water and muck on their way to becoming a Marine or going into some other line of work, October 7, 1971. (Photo by Eddie Adams/AP Photo)

Man prepares wigs as he waits for customers in downtown Johannesburg, on August 5, 2014. Some estimates put Africa's dry hair industry at as much as $6 billion a year; Nigerian singer Muma Gee recently boasted that she spends 500,000 naira ($3,100) on a single hair piece made of 11 sets of human hair. (Photo by Siphiwe Sibeko/Reuters)

“APOPO’s Training Center, situated on Sokoine Univeristy of Agriculture (SUA) in Tanzania, was established in 2000 to accommodate training and testing of mine detection rats in near-to-real conditions”. – APOPO

Photo: MDR (Mine Detection Rat) learn to look for mines. (Photo by APOPO's HeroRATs)

After a cold night the small North Devon villages of Appledore and Instow wake up to an amazing scene as the sun rises over the River Torridge estuary, Devon, UK on October 19, 2018. (Photo by Terry Mathews/Alamy Live News)

A girl yawns as she and others wait for the start of their first day in school, an occasion known as the Day of Knowledge, in the small town Ignalina, some 110km (68 miles) north of the capital Vilnius, Lithuania, Monday, September 2, 2019. (Photo by Mindaugas Kulbis/AP Photo)

Tom Kaulitz and Heidi Klum attend Heidi Klum's 20th Annual Halloween Party presented by Amazon Prime Video and SVEDKA Vodka at Cathédrale New York on October 31, 2019 in New York City. (Photo by Craig Barritt/Getty Images for SVEDKA)

Public Space series, 2015. This series by Morteza Niknahad and Behnam Zakeri tends toward cinema, taking an almost cartoonish view of modern life in Iran. This work was inspired by the social life of dolphins. (Photo by Morteza Niknahad and Behnam Zakeri/The Guardian)

People are seen at Avalon Beach on December 18, 2020 in Sydney, Australia. A cluster of Covid-19 cases on the northern beaches of Sydney has grown to 28, prompting NSW health officials to urge residents of affected suburbs to stay home. Traffic at Sydney Airport has increased as people rush to leave the city with several states imposing quarantine restrictions for New South Wales residents. (Photo by Jenny Evans/Getty Images)