Saudi youths demonstrate a stunt known as “sidewall skiing” (driving on two wheels) in the northern city of Hail, in Saudi Arabia March 30, 2013. Performing stunts such as sidewall skiing and drifts is a popular hobby amongst Saudi youths. (Photo by Mohamed Al Hwaity/Reuters)

Four-man bicycle is powered by five chains and has brakes on both its wheels, 1948. The bike was built by Art Rothschild (top position) who broke three ribs while learning how to ride it. (Photo by Wallace Kirkland/Time & Life Pictures)

“The Personal Urban Mobility and Accessibility (PUMA) is an experimental electrically powered road vehicle created by Segway and adopted by General Motors as a concept vehicle representing the future of urban transportation. It operates on two wheels placed side-by-side, a layout that differs in placement from motorcycles which instead have their two wheels placed at the front and rear”. – Wikipedia

The Project P.U.M.A. (Personal Urban Mobility and Accessibility) prototype is displayed for the media April 7, 2009 in New York City. (Photo by Mario Tama/Getty Images)

Su Daocheng rides his home-made mechanical horse vehicle on a street in Shiyan, Hubei province January 18, 2015. Su spent 2 months making this 1.5 metre high and 2 metre long horse, which weighed 250 kilograms with 4 legs and 2 supportive wheels, local media reported. (Photo by Reuters/Stringer)

Participants wearing historical attire compete on historical high wheel Penny Farthing bicycles in the traditional 'One Mile Race' at Letna Park in Prague, Czech Republic, November 7, 2015. The meeting of Penny Farthing bicycles is taking place for the 22th time. (Photo by Filip Singer/EPA)

Japanese macaque monkeys enjoy sitting in the hot springs at Jigokudani-Onsen (Hell Valley) on January 23, 2005 in Jigokudani, Nagano-Prefecture, Japan. Japanese Macaques, also known as snow monkeys are the most northerly nonhuman primate in the world. In 1963 a female Macaque ventured into the hot springs to retrieve some soybeans. This behaviour was adopted by other monkeys, and eventually by the entire troop. This Macaque troop regularly visits the Jigokudani-Onsen springs to escape the cold. The hot springs are said to help relieve nerve pain and fatigue. (Photo by Koichi Kamoshida/Getty Images)

Leon Samson, 24-year-old showman, grimaces as an automobile is driven across his chest at Perth, Australia on October 9, 1960. Samson said the towel on his chest is to prevent the wheel from tearing his flesh. (Photo by AP Photo)