Socialite Kathy Hilton attends the Prudential Financial Grand Prix Hamptons Classic Horse Show August 31, 2003 in Bridgehampton, New York.

A Border Collie competes in the Flyball during The World Dog Games at Acer Arena on October 31, 2009 in Sydney, Australia. (Photo by Brendon Thorne/Getty Images)

Chinese butchers catch a pig to slaughter on January 31, 2005 in Jinzhai County, Anhui Province, China. (Photo by Cancan Chu/GettyImages)

Keira Knightly attends the UK Gala Premiere of “A Dangerous Method” at The Mayfair Hotel on January 31, 2012 in London, England. (Photo by Stuart Wilson/Getty Images)

A competitor participates in the Tough Mudder challenge near Henley-on-Thames in southern England May 2, 2015. (Photo by Eddie Keogh/Reuters)

A devotee smiles as she offers prayers during the Swasthani Brata Katha festival in Kathmandu, Nepal January 12, 2017. (Photo by Navesh Chitrakar/Reuters)

A customer grimaces in pain as she gets a tattoo on her arm at the 21st International Tattoo Convention Berlin on December 3, 2011 in Berlin, Germany. The annual tattoo trade fair runs from December 2–4, 2011. (Photo by Adam Berry/Getty Images)