Protesters begin to gather ahead of the UK Student Climate Network's Global Climate Strike at Millbank in London, England on September 20, 2019. (Photo by Gareth Fuller/PA Images via Getty Images)

The Vattenfall Solar Team car “Nuna” from the Netherlands competes in the Challenger class on Day 2 of the 2019 Bridgestone World Solar Challenge at Elliott on October 14, 2019 in Elliott Australia. Teams from across the globe are competing in the 2019 World Solar Challenge – a 3000 km solar-powered vehicle race between Darwin and Adelaide. The race starts on the 13th of October in Darwin in the Northern Territory and travels the Stuart Highway to Port Augusta and then via Highway 1 to finish in the City of Adelaide in South Australia. (Photo by Mark Evans/Getty Images for SATC)

Advanced Space Suit Engineer at NASA Kristine Davis wears the xEMU prototype space suit for the next astronaut to the moon by 2024, during its presentation at NASA headquarters in Washington, U.S., October 15, 2019. (Photo by Carlos Jasso/Reuters)

A Kurdish fighter from the People's Protection Units (YPG) fires his rifle at Islamic State militants as he runs across a street in Raqqa, Syria, July 2017. (Photo by Goran Tomasevic/Reuters)

A woman walks past servicemen of the self-proclaimed Donetsk People's Republic (DNR), who take part in a rehearsal for the Victory Day parade in Donetsk, Ukraine on May 3, 2018. (Photo by Alexander Ermochenko/Reuters)

Video bloggers stream live broadcast of an event to celebrate the fourth birthday of the world's only giant panda triplets, Meng Meng, Shuai Shuai and Ku Ku, at Chimelong Safari Park in Guangzhou, China July 29, 2018. (Photo by Bobby Yip/Reuters)

A man in a wartime uniform, poses for a photo on an abandoned tank at a beach, ahead of the 60th anniversary of Second Taiwan Straits Crisis against China, in Kinmen, Taiwan on August 19, 2018. (Photo by Tyrone Siu/Reuters)

A pigeon eating cherries in Bydgoszcz, Poland on September 14, 2018. The pigeon was captured at dinnertime, as he was caught on camera with its mouth full of a cherry. (Photo by Piotr Grny/Caters News Agency)