Joseph Pilates was always into fitness, as were his parents. But the athlete and bodybuilder didn't come up with the fitness regimen named after him until World War I, when he was living in England. As a German national, he was interned in a camp on the Isle of Man, along with ten of thousands of other foreigners. Due to the German blockade, they were starving. Pilates wanted to do something, and was inspired by observing cats.
“Though they were nothing but skin and bones — even the most animal-loving prisoners could hardly spare them anything from their own pitiful rations when their own children were begging to be fed — they were lithe and springy and terribly efficient as they aimed for their prey,” waxed Sports Illustrated journalist Robert Wernick in a 1962 interview with Pilates. The answer, apparently, was stretching: Pilates observed the cats constantly stretching and limbering up, and used that to inspire and refine the poses of his own exercise system. Pilates would later boast that when the 1918 flu pandemic — which killed approximately 50 million people worldwide — hit the camp, none of the men practicing his exercises got sick.