When was Velcro invented?

After a hunting trip in the Swiss Alps in 1941, de Mestral noticed burdock burrs clinging to his clothes and his dog's fur. Under a microscope he saw the burrs were covered with tiny hooks that caught on loops in fabric. He spent years developing a synthetic version, finally succeeding with nylon, and filed his patent in 1951, receiving it in Switzerland in 1955. The name Velcro combines the French words 'velours' (velvet) and 'crochet' (hook). NASA's use of hook-and-loop fasteners in the Apollo programme helped make them famous.