In this May 14, 2016 photo, children wearing their school backpacks climb on a cliff using a bamboo ladder on their way home from school in Zhaojue county, southwest China's Sichuan province. A village in China's mountainous west where schoolchildren must climb an 800-meter (2,625-foot)-high bamboo ladder secured to a sheer cliff face may get a set of steel stairs to improve it's safety. (Photo by Chinatopix via AP Photo)

Long-tailed mayflies (Palingenia longicauda) mate on the surface of the Tisza river near Tiszakurt, Hungary, June 14, 2016. Millions of these short-lived mayflies engage in a frantic rush to mate and reproduce before they perish in just a few hours during “Tiszaviragzas” or Tisza blooming season from late spring to early summer every year. (Photo by Laszlo Balogh/Reuters)

Residents carry an injured woman rescued from a collapsed house in Funing county in Yancheng city of eastern China's Jiangsu Province on Thursday June 23, 2016. A powerful tornado hit Thursday, with reports of dozens killed and large numbers of buildings destroyed in the eastern Chinese province of Jiangsu, according to state media. (Photo by Chinatopix via AP Photo)

A commuter exits a closed off station after a subway train derailment, Tuesday, June 27, 2017, in the Harlem neighborhood of New York. A subway train derailed near a station in Harlem on Tuesday, frightening passengers and resulting in a power outage as people were evacuated from trains along the subway line. The Fire Department of New York said a handful of people were treated for minor injuries at around 10 a.m. It said there was smoke but no fire. Delays were reported throughout the subway system. (Photo by Mary Altaffer/AP Photo)

A demonstrator uses a TV case as a facemask during a protest to demand justice for Daniel Prude, on September 3, 2020 in New York City. Protests were planned in New York September 3 over the death of Daniel Prude, a black man that police hooded and forced face down on the road, according to video footage that prompted a probe from the state's attorney general. (Photo by Kena Betancur/AFP Photo)

Drinkers leave the bars as police patrol in Soho, in central London on September 24, 2020 as the clock nears 10pm, on the first day of the new earlier closing times for pubs and bars in England and Wales, introduced to combat the spread of the coronavirus. Britain has tightened restrictions to stem a surge of coronavirus cases, ordering pubs to close early and advising people to go back to working from home to prevent a second national lockdown. (Photo by Tolga Akmen/AFP Photo)

An undated handout photo made available by the Zerynthia Association shows the pupa of an amicta moneiba, a recently discovered species of moth endemic to La Gomera and El Hierro islands in the Canary Islands, Spain (issued 01 July 2020), as those two islands pulled apart from the rest of the Canary Islands 2.5 million years ago. The Institute of Evolutionary Biology of the Spanish National Research Council (CSIC) and the Zerynthia Association have recently discovered two new moth species in El Hierro and La Gomera. (Photo by Yeray Monasterio/Zerynthia/EPA/EFE)

A voter wearing protective face mask shows off her finger marked with ink indicating she voted as she leaves a polling station Sunday, November 8, 2020, in Yangon, Myanmar. Voting was underway in Myanmar’s elections on Sunday, with the party of Nobel Peace Prize laureate Aung San Suu Kyi heavily favored to retain power it had wrestled from the powerful military five years ago. (Photo by Thein Zaw/AP Photo)