Tennis shoes are called sneakers because they don't make noise when you walk, and so you can “sneak up” on someone and not be heard.
Sneakers were only worn by athletes until Hollywood picked up on the fashion in the 1950s, when teen icon James Dean was photographed wearing a pair.
Since then, young people around the world have been wearing them as an unofficial uniform.
Sneakers are multipurpose, and people wear them for hiking, going to the gym, or even to walk to the office.