Retired teacher Geoff Ostling displays his tattooed skin at a portrait session at his home in Petersham on May 11, 2009 in Sydney, Australia. The 62-year old has pledged to donate his skin to the National Gallery in Canberra after his death. Ostling, who did not get his first tattoo until he was in his forties, is now covered in the artwork by artist eX de Merci from neck to ankle with the theme 'all the flowers of a Sydney garden'. (Photo by Lisa Maree Williams/Getty Images)

In this photo taken April 15, 2015, Clay Hielscher of Overbrook, Kan., poses for a photo in his home made Iron Man suit. While he enjoys building the battlesuits of his favorite super hero, Hielscher said the real reason he is so passionate about his pastime is his 11-year-old daughter, Kyrianna. They design and construct the suits together. (Photo by Chris Neal/AP Photo/The Topeka Capital-Journal)

“Liu Bolin is an artist born in China’s Shandong province in 1973, and he earned his Bachelor of Fine Arts from the Shandong College of Arts in 1995 and his Master of Fine Arts from the Central Academy of Fine Arts in Beijing in 2001. His work has been exhibited in museums around the world. Also known as “The Invisible Man”, Liu Bolin's most popular works are from his “Hiding in the City” series; photographic works that began as performance art in 2005”. – Wikipedia. (Photo by Reuters/China Daily)

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)

Undated David Yarrow handout photo of a gorilla as the self-taught wildlife photographer promotes his book, Encounter. (Photo by David Yarrow/Clearview/PA Wire)

Blacksmith Johann Schmidberger works on a suit of armour for the Vatican's Swiss Guards at his workshop in Molln, Austria, March 29, 2017. Austrian blacksmiths who produce ceremonial suits of armour for the Vatican's Swiss Guards are close to the end of their current deal to do so, and say supplying the suits will not now be an issue for many years to come. One of the drawbacks of the Swiss Guards' medieval uniforms is that the craftsmanship needed to make them is disappearing. (Photo by Leonhard Foeger/Reuters)