Sometime in the 1950s, all over California, surfers got the idea to try surfing on pavement. It seems that several people got the idea at the same time. Skateboarding was just sort of spontaneously created, without guidance or planning.
These first skateboarders started with wooden boxes or boards with roller skate wheels slapped on the bottom. It was a crazy time, more about having fun than forming skateboarding into something that would rock the planet for the next 60 years.
Slowly, the wooden boxes with wheels turned into planks, and eventually companies were producing decks of pressed layers of wood -- similar to the skateboard decks of today.
To find out more about the history of skateboards, read "Skateboarding: A Brief History."