A protesting student runs past a burning bus off campus outside the University of the Witwatersrand in Johannesburg, South Africa on Monday, October 10, 2016. Tear gas and water cannon were fired as hundreds of students protested at the university amid a bitter national dispute with university managers and the government over demonstrators' demands for free education, forcing student into the neighbouring city streets. (Photo by AP Photo)

A Shiite fighter from the Hashed al-Shaabi (Popular Mobilisation) patrols in the village of Ayn Nasir, south of Mosul, on October 29, 2016, after recapturing it from Islamic State group jihadists in an ongoing operation to retake the city of Mosul. Iraqi paramilitary forces launched an operation to cut the Islamic State group's supply lines between its Mosul bastion and neighbouring Syria, opening a new front in the nearly two-week-old offensive. (Photo by Ahmad Al-Rubaye/AFP Photo)

Tommy Lindsey holds an enormous maple leaf that he found in Mount Vernon, Wash., October 28, 2013. Lindsey was walking with his family when he picked up the leaf that is more than two feet from stem to tip and more than 21 inches wide. (Photo by Frank Varga/The Skagit Valley Herald)

These photos and video were taken in the Russian city of Astrakhan on the evening of June 7th, 2012. (Photo by Maxim Korotshenko)

A full scale replica of the sphinx, which is part of an unfinished movie and animation tourism theme park, is pictured in Chuzhou, Anhui province, March 3, 2015. (Photo by Reuters/Stringer)

“Business-class” cabins are seen at First Cabin hotel, which was converted from an old office building, in Tokyo, July 3, 2015. Record tourists to Japan are stretching the ability of hotels to accommodate them in a sector constrained by high costs, forcing developers to think out of the box for means to quickly increase lodging options without breaking the bank. (Photo by Toru Hanai/Reuters)

A man shaves blocks of salt from the Danakil Depression on 28 March 2017, in Afar, Ethiopia. Every morning, hundreds of men converge on a dry lakebed in a remote corner of Ethiopia, where they cleave the ground open with handaxes to extract salt, just as their fathers and grandfathers once did. (Photo by Zacharias Abubeker/AFP Photo)

Garbage, including plastic waste, is seen at the beach of Costa del Este, in Panama City, on April 19, 2021. Every two weeks, Marine Biology students descend about five meters in the sea to take care of a coral nursery of the staghorn species (Acropora cervicornis) in Portobelo, Panama, with which they aim to restore reefs damaged by climate change and pollution, as part of the Reef2Reef project. (Photo by Luis Acosta/AFP Photo)