Mark Dill and Brit Thacker practice acro-yoga as approximately 70,000 people from all over the world gather for the 30th annual Burning Man arts and music festival in the Black Rock Desert of Nevada, U.S. August 29, 2016. (Photo by Jim Urquhart/Reuters)

A girl reacts as she is tattooed during the third International Tattoo Week Rio 2016 festival in Rio de Janeiro, Brazil, January 22, 2016. (Photo by Pilar Olivares/Reuters)

Festivalgoers dance during the Balaton Sound music festival in Zamardi, Hungary, July 5, 2018. Balaton Sound is one of Europe's largest open air electronic music festivals. Held annually since 2007 on the southern bank of Lake Balaton, Hungary, it features live acts and DJ's from all around the world, from established artists to new names. The event was co-created by the organizers of Sziget Festival. (Photo by Bernadett Szabo/Reuters)

Trainees of the Tianjiao Special Guard/Security Consultant bodyguard training camp watch their instructor use a scarf to cover a student's head during a demonstration of close-quarter combat skills at a special course on flight safety inside a scale model of a passenger jet at a flight attendant training centre on the outskirts of Beijing, March 18, 2014. Inspired by the missing Malaysia Airlines Flight MH370, the company wanted to emphasize the importance of aviation safety by teaching their trainees emergency evacuation procedures and close-quarter combat skills to handle situations such as natural disasters and plane hijacks, according to the company. (Photo by Jason Lee/Reuters)

A Hindu villager rides a motorcycle past an altar ahead of the annual Kasada festival at the Mount Bromo in Indonesia's East Java province, July 30, 2015. The Kasada festival will be held on August 1, when the worshippers throw offerings such as livestock and other crops into the volcanic crater of Mount Bromo to give thanks to the Hindu gods for ensuring their safety and prosperity. (Photo by Reuters/Beawiharta)

Revellers take part in the Holi Party Festival at the Niemeyer Center in Aviles, northern Spain, August 29, 2015. The event is inspired by the Hindu Holi spring festival of colour celebrated mostly in India but has recently spread to other countries. (Photo by Eloy Alonso/Reuters)

Punks gather in Blackpool for the annual Rebellion Punk Rock Festival on August 8, 2014 in Blackpool, England. This weekend a clash of musical cultures hits the famous seaside town as pogoing punks attending the annual Rebellion Festival at The Winter Gardens come shoulder to shoulder with traditional holidaymakers and seasiders. (Photo by Christopher Furlong/Getty Images)