“DC3 Wreck”. A capture of a US military DC3 plane wreck at the southern black beach in Iceland. Photo location: Iceland. (Photo and caption by Naian Feng/National Geographic Photo Contest)

A tourist is seen at the Caka Salt Lake in Wulan County, northwest China's Qinghai Province, September 4, 2020. (Photo by Zhang Long/Xinhua News Agency)

A face mask discarded in a forest in the Taunus region near Frankfurt, Germany, Sunday, October 18, 2020. (Photo by Michael Probst/AP Photo)

An Iranian woman wearing a face mask walks on a street in Tehran, Iran, 19 October 2020. According to the Iranian Health ministry, Iran reported its highest daily COVID-19 death toll of 337 and 4,251 new infections in past 24 hours as it appears that Iran is in a third wave of COVID-19 outbreak. (Photo by Abedin Taherkenareh/EPA/EFE)

Gentoo penguins watching Christmas films at the Sea Life London aquarium on November 30, 2020. The attraction has installed two TVs, showing festive films, outside the penguin enclosure to prepare them for the stimulation of guests returning on Wednesday after the UK’s lockdown is lifted. (Photo by Yui Mok/PA Images via Getty Images)

Two citizens splash hot water which is quickly frozen in the cold air on January 7, 2021 in Beijing, China. A strong cold wave sweeps across China as the Chinese capital Beijing recorded 19.5 Celsius below zero on 06 January morning, the lowest temperature since 1966, according to meteorological authorities. (Photo by Peng Yucai/VCG via Getty Images)

Two costumed reveler seen at the City center where normally thousands of revelers dressed in carnival costumes would celebrate the Rose Monday parade on the streets in Mainz, Germany, 15 February 2021. The Rose Monday Parade has been cancelled due to the coronavirus Covid-19 pandemic. (Photo by Ronald Wittek/EPA/EFE)

South Korean tightrope walker Nam Chang-dong performs “Jultage” or Tightrope walking during the traditional festival “Dano” at Namsan Hanok village in Seoul, South Korea, 14 June 2021. The festival falls on the fifth day of the fifth month of the lunar calendar. Only 30 audience members were allowed to attend the performance amid the coronavirus COVID-19 pandemic. (Photo by Jeon Heon-Kyun/EPA/EFE)