A Palestinian social activist working for the International South South Cooperation (Cooperazione Internazionale Sud Sud, or CISS) entertain children who are patients inside a hospital in Gaza City August 31, 2015. Activists working for the Italian non-profit NGO use entertainment and humour to help bring treatment to children suffering from psychological trauma in the Gaza Strip. (Photo by Mohammed Salem/Reuters)

Photographers work on the red carpet after the screening of the film “Mad Max: Fury Road” out of competition at the 68th Cannes Film Festival in Cannes, southern France, May 14, 2015. (Photo by Regis Duvignau/Reuters)

Crew members work to secure a hot air balloon after landing during the 2015 Albuquerque International Balloon Fiesta in Albuquerque, New Mexico, October 4, 2015. (Photo by Lucas Jackson/Reuters)

One of the invited tattoo artists, Tom Storm, works on the arm of Kerrie Hibbert at the 2017 Tattoo Collective event at the Old Truman Brewery in London, England on February 17, 2017. (Photo by PA Wire)

A young woman employee of North American Aviation Incorporated, working over the landing gear mechanism of a P-51 fighter plane, Inglewood, California, 1942. (Photo by Alfred T. Palmer/Buyenlarge/Getty Images)

A man works on a tattoo during the 8th Expotattoo Colombia Fair in Medellin, Antioquia department, Colombia on July 14, 2017. The event – which is in its eighth year – attracted plenty of colourful characters. (Photo by Joaquin Sarmiento/AFP Photo)

A Chinese couple take pictures in an interactive installation art work named “You and Me” on Valentine's Day at 798 Art Zone on February 14, 2012 in Beijing, China. (Photo by Feng Li/Getty Images)

Prostitutes working on 10th Ave in New York, USA on June 29, 1997. (Photo by Jon Naso/NY Daily News Archive via Getty Images)