This photo taken on April 4, 2021 shows migratory birds flying over a wetland near the Yalu River in Dandong, in China's northeastern Liaoning province. (Photo by AFP Photo/China Stringer Network)

A model has her hair and make-up done backstage ahead of a show of British designer Jasper Conran at the London Fashion Week, in London, Britain, 15 September 2018. (Photo by Tolga Akmen/EPA/EFE)

Sukhoi Su-30SM jet fighters of the Russkiye Vityazi (Russian Knights) aerobatic team perform during a demonstration flight in Krasnoyarsk, Russia October 6, 2018. (Photo by Ilya Naymushin/Reuters)

A Palestinian girl wear a face mask during a lockdown imposed following the discovery of coronavirus cases in the Gaza Strip, Thursday, August 27, 2020. On Wednesday Gaza's Hamas rulers extended a full lockdown in the Palestinian enclave for three more days as coronavirus cases climbed after the detection this week of the first community transmissions of the virus in the densely populated, blockaded territory. (Photo by Hatem Moussa/AP Photo)

New Zealand Defence Force personal perform a haka during Te Rau Aroha, an evening to commemorate Maori service in the New Zealand Armed Forces on February 05, 2020 in Waitangi, New Zealand. The Waitangi Day national holiday celebrates the signing of the treaty of Waitangi on February 6, 1840 by Maori chiefs and the British Crown, that granted the Maori people the rights of British Citizens and ownership of their lands and other properties. (Photo by Fiona Goodall/Getty Images)

A girl looks on after a fire broke out in a slum in Dhaka, Bangladesh, March 11, 2020. (Photo by Mohammad Ponir Hossain/Reuters)

Police intervene as two women fight at a pro-law enforcement rally that clashed with counter protesters demonstrating against racial inequality, in Denver, Colorado, U.S. July 19, 2020. (Photo by Kevin Mohatt/Reuters)

The competition, which is run by the Royal Observatory Greenwich in association with BBC Sky at Night Magazine, is now in its sixth year and has received over 2,500 entries. Photo: Centre of the Heart Nebula by Ivan Eder (Hungary). Situated 7500 light years away in the “W”-shaped constellation of Cassiopeia, the Heart Nebula is a vast region of glowing gas, energized by a cluster of young stars at its centre. The image depicts the central region, where dust clouds are being eroded and moulded into rugged shapes by the searing cosmic radiation. (Photo by Ivan Eder)