After taking his dog for a walk one day in the early 1940s, George de Mestral, a Swiss inventor, became curious about the seeds of the burdock plant that had attached themselves to his clothes and to the dog’s fur.

Under a microscope, he looked closely at the hook-and-loop system that the seeds use to hitchhike on passing animals aiding seed dispersal, and he realised that the same approach could be used to join other things together. The result was Velcro.
Writer: Wikipedia.org