Viking re-enactors representing the rival armies of the Vikings and Anglo-Saxons skirmish near Clifford’s Tower during the Jorvik Viking Festival on February 23, 2019 in York, England. The annual Jorvik Viking Festival held in York is recognised as the largest event of its kind in Europe. This year the festival remembers the role that the Viking women played during those turbulent times. (Photo by Christopher Thomond/The Guardian)

Sun Rongchun, 57, exercises with an improvised cervical traction device attached to a high bar at a sports complex in Shenyang, Liaoning province, China on April 9, 2019. (Photo by Sheng Li/Reuters)

A man passes by a wall with graffiti in Beirut, Lebanon, on May 29, 2019. (Photo by Bilal Jawich/Xinhua News Agency/Alamy Live News)

An Indian Sadhu, or Hindu holy man, performs a yoga position on International Yoga Day at Kamakhya temple in Gauhati, India, Friday, June 21, 2019. (Photo by Anupam Nath/AP Photo)

Police officers hold a revolver as they offer prayers to their weapons as part of a ritual at their headquarters on the occasion of Dussehra, or Vijaya Dashami, festival in Ahmedabad, India, October 8, 2019. (Photo by Amit Dave/Reuters)

A local farmer Theophilus Mwendwa runs through a swarm of desert locusts to chase them away in the bush near Enziu, Kitui County, some 200km east of the capital Nairobi, Kenya, 24 January 2020. Large swarms of desert locusts have been invading Kenya for weeks, after having infested some 70 thousand hectares of land in Somalia which the United Nations Food and Agriculture Organisation (FAO) has termed the “worst situation in 25 years” in the Horn of Africa. FAO cautioned that it poses an “unprecedented threat” to food security and livelihoods in the region. (Photo by Dai Kurokawa/EPA/EFE)

In this artist's impression supplied by the ESO (European Southern Observatory) on April 25, 2007, the planetary system around the red dwarf, Gliese 581, is pictured showing what astronomers believe is the most earth like planet found outside our solar system to date. Using the ESO 3.6-m telescope in Chile, astronomers have uncovered the planet which could have water running on its surface. The planet orbits the faint star Gliese 581, which is 20.5 light-years away in the constellation Libra. (Photo by ESO via Getty Images)

Natalie Dormer attends the mtvU Fandom Awards at MTV Fan Fest at Comic-Con, July 24, 2014, in San Diego. (Photo by Jordan Strauss/Invision for MTV/AP Images)