Revellers continue to party and dance through the night and day during the second day of the San Fermin Running Of The Bulls festival, on July 7, 2014 in Pamplona, Spain. The annual Fiesta de San Fermin, made famous by the 1926 novel of US writer Ernest Hemmingway “The Sun Also Rises”, involves the running of the bulls through the historic heart of Pamplona. (Photo by Christopher Furlong/Getty Images)

Participants are covered by colored powder as they compete in The Color Run, a five-kilometre untimed race, in Hanoi, Vietnam September 26, 2015. Approximately 7,000 participants took part in Hanoi's first Color Run, reported local media. (Photo by Reuters/Kham)

Festival-goers enjoy the mud during the annual Boryeong Mud Festival at Daecheon Beach on July 18, 2015 in Boryeong, South Korea. The mud, which is believed to have benefical effects on the skin due to its mineral content, is sourced from mud flats near Boryeong and transported to the beach by truck. (Photo by Chung Sung-Jun/Getty Images)

Owner Nicole Graham works with volunteers from CFA and SES tries to dig out her horse “Astro” who became stuck up to his neck in mud at Avalon Beach on February 26, 2012 in Geelong, Australia. The tide was fast-rising, but the rescuers managed to get him out in time. (Photo by Peter Ristevski/Newspix)

Participants take part in the Mud Day race, a 13km obstacle course, on March 24, 2017 in the Israeli Mediterranean coastal city of Tel Aviv. (Photo by Jack Guez/AFP Photo)

A woman takes part in an extreme run competition in Zhodino, east of Minsk, September 26, 2015. (Photo by Vasily Fedosenko/Reuters)

Participants run through coloured powder during the YARKOcross colour run race in Almaty, Kazakhstan, June 5, 2016. (Photo by Shamil Zhumatov/Reuters)

A participant runs through colored powder as she takes part in the Get Rainbowed run in Prague May 23, 2015. Get Rainbowed is a five-kilometre race with the aim of promoting a healthy lifestyle. (Photo by David W. Cerny/Reuters)