Revellers in Leeds, United Kingdom were excited to be out and about again on July 18, 2021. At a minute past midnight, England dropped most of its remaining Covid-19 social restrictions, such as those requiring indoor mask-wearing and limits on group gatherings. These changes come despite rising infections, pitting the country's vaccination programme against the virus's more contagious Delta variant. (Photo by Ioannis Alexopoulos/PA Wire Press Association via Getty Images)

A woman cools off at a fountain in central Cordoba, southern Spain, 11 August 2021. Andalucia was put on orange alert for high temperatures, with a new heatwave forecast to reach temperatures of over 41 degrees Celsius in the region. (Photo by Salas/EPA/EFE)

A masked dancer performs as part of “Devi Pyankha” (Devi Dance) to mark the beginning of the Indra Jatra Festival in Kathmandu, Nepal on September 15, 2021. Nepali celebrate the Indra Jatra festival to worship “Indra”, the god of rain and to mark the end of monsoon season. (Photo by Sunil Sharma/ZUMA Press Wire/Rex Features/Shutterstock)

Postal worker Eddie Smith, dressed as Santa Claus, waves to a neighbor on his mail route in Washington, U.S., December 21, 2021. (Photo by Evelyn Hockstein/Reuters)

North Korean youngsters sing and play accordions to entertain foreign visitors including United Nations Secretary General Kurt Waldheim, who visited Pyongyang, May 4, 1979. Visitors report music education in North Korea begins at an early age and is taken seriously by children and adults. (Photo by Peter Arnett/AP Photo)

A group of teachers and their student use makeshift raft as they cross the street during flood that hit Ranomeeto Barat village in Konawe Selatan, Sulawesi island, Indonesia, July 10, 2018. (Photo by Jojon/Reuters/Antara Foto)

A girl stretches next to a pram on the embankment of the Moskva river in Moscow on October 18, 2018. The European part of Russia enjoys an unusually warm weather for the season with temperatures reaching up to 22 degrees centigrade. (Photo by Mladen Antonov/AFP Photo)

A participant races in the Brompton World Championship in Bern, Switzerland October 21, 2018. (Photo by Stefan Wermuth/Reuters)