A medical staff member rests next to a patient infected with Covid-19 in the intensive care unit of Lozenets Hospitalin Sofia on November 9, 2021. Bulgaria is among the countries with the highest number of deaths compared to its population. (Photo by Nikolay Doychinov/AFP Photo)

Aoife Ni Heochaidh enjoys the sunrise as she welcomes winter solstice at the 5000-year-old stone age passage tomb of Newgrange in the Boyne Valley, as entry inside the chamber is closed for the second year due to coronavirus disease (COVID-19) pandemic, in Newgrange, Ireland, December 21, 2021. (Photo by Clodagh Kilcoyne/Reuters)

A woman, covered in coloured powder, takes part in the 2019 Colour Run, a 5 km run around the Luzhniki Olympic Complex, in Moscow, Russia on June 02, 2019. (Photo by Sefa Karacan/Anadolu Agency/Getty Images)

Ten-year-old Macy Friday, front left, reacts as she looks back at her family after meeting Hillary Clinton, front right, as she campaigns for U.S. Sen. Mark Udall, D-Colo., back, during a stop in the newly-renovated Union Station in Denver on Monday, October 13, 2014. Clinton appeared at an event to raise money for Udall's current re-election campaign and then headed to Las Vegas for another appearance on Monday night. (Photo by David Zalubowski/AP Photo)

A participant prepares for the Red Bull Air Race World Championships in Abu Dhabi, United Arab Emirates on February 6, 2017. (Photo by Red Bull Content Pool/SIPA Press/Rex Features/Shutterstock)

A worker applies colour to strings which will be used to fly kites, by a roadside in Ahmedabad, India, November 23, 2017. (Photo by Amit Dave/Reuters)

A dancer waits to perform during festivities marking the start of the annual harvest festival of “Onam” in Kochi, India, August 19, 2015. The ten-day-long Hindu festival is celebrated annually in India's southern coastal state of Kerala to commemorate the return of King Mahabali to his beloved subjects. (Photo by Sivaram V/Reuters)

A monkey is led by its trainer Qi Defang during training for a circus in Suzhou, Anhui province, November 29, 2014. Suzhou is known as the hometown of circus troupes in China and has more than 300 circus troupes. (Photo by William Hong/Reuters)