Heelys are the shoes with a wheel in the heel. They allow you to walk, run and switch to a roll at any moment.
Heelys were first invented by Roger Adams in 2000 while he was on vacation in Huntington Beach, CA. While watching kids skate up and down the streets on their inline skates, Roger thought of the idea of a shoe that could roll on command by just shifting your body weight from the front of your feet to your heels. He quickly got to work in his garage, cutting out the heels of a pair of Nike running shoes, running rods through each heel, and using one of the wheels bearings that come on a skateboard. Those first pair of Heelys needed some work, but when they eventually rolled into stores they sold out in a matter of minutes.
Since then, Heelys has gone on to sell millions of pairs of shoes in over 70 countries, allowing kids and adults to skate in malls, parking lots, or on pretty much any stretch of concrete they can find.