Snow skiing is a group of sports and activities holding in common the use of skis, devices which slide on snow and attach with ski bindings and ski boots to people's feet. Skiing sports differ from snowshoeing in that skis slide, and they differ from ice-skating, water skiing, and in-line skating by being performed on snow. Although snowboarding shares the general characteristics of skiing sports, it evolved from surfing and skateboarding and so is not considered a type of skiing. Skiing can be grouped into two general categories. Nordic skiing is the oldest category and includes sport that evolved from skiing as done in Scandinavia. Nordic style ski bindings attach at the toes of the skier's ski boots, but not at the heels. Alpine skiing includes sports that evolved from skiing as done in the Alps. Alpine bindings attach at both the toe and the heel of ski boots. These two categories overlap with some sports potentially fitting into both. However, binding style and history indicate that each skiing sport is more one than the other. Some skiing sports such as Telemark skiing have elements of both categories, but its history in Telemark, Norway and free-heel binding style place Telemark skiing firmly in the Nordic category.