A toboggan is a simple sle used on snow, to carry one or more people (often children) down a hill or other slope, for recreation. Designs vary from simple, traditional models to modern engineered composites. A toboggan differs from most sleds or sleighs in that it has no runners or skis on the underside. The bottom of a toboggan rides directly on the snow. The Olympic version of this sport is bobsleigh, which extends the curved front of the toboggan to full sidewalls and includes runners. Some parks include designated toboggan hills where ordinary sleds are not allowed and which may include toboggan runs similar to bobsleigh courses.