Rock climbing, like hiking, is a widely practiced sport in its own right. The essentials of rock climbing are often learned on local cliffs, where the teamwork of mountaineering, the use of the rope, and the coordinated prerequisites of control and rhythm are mastered. The rope, the artificial anchor, and carabiner (or snap link, a metal loop or ring that can be snapped into an anchor and through which the rope may be passed) are used primarily as safety factors. An exception occurs in tension climbing, in which the leader is supported by a judiciously placed series of anchors and carabiners through which the rope is passed. He or she is then supported on the rope by fellow climbers while slowly moving upward to place another anchor and repeat the process.