Harold E. Edgerton's high-speed photograph of a woman dancer in a flowing dress performing a cartwheel, 1940.
"At a photography fair in Chicago, Kodak introduced Edgerton's Kodatron strobe with a demonstration of its ability to record rapid movement. At 1/3,000 of a second, the flash stopped the dancer's momentum in the middle of her seemingly impossible move." 

Always nice to have a helping hand... Joseph Janney Steinmetz - Acrobats rehearsing at the Ringling Circus, 1940’s.
Found via Gold Lion Healing Arts