climbing is an outdoor recreational activity. The participants (known as campers) leave urban areas, their home region, or civilization and enjoy nature while spending one or several nights outdoors, usually at a campsite. Camping may involve the use of a tent, caravan, motorhome, a primitive structure, or no shelter at all. Camping as a recreational activity became popular in the early 20th century. Campers frequent national or state parks, other publicly owned natural areas, and privately owned campgrounds. Camping is a key part of many youth organizations around the world, such as Scouting. It is used to teach self-reliance and teamwork.