Rock climbing
Rock climbing, broadly speaking, is the act of ascending steep rock formations. Normally, climbers use gear and safety equipment specifically designed for the purpose. Strength, endurance, and mental control, as well as agility and balance, are required to cope with tough, dangerous physical challenges, and knowledge of climbing techniques and the use of essential pieces of gear and equipment are crucial.

# History
Although the practice of rock climbing was an important component of Victorian mountaineering in the Alps, it is generally thought that the sport of rock climbing began in the last quarter of the nineteenth century in various parts of Europe. Rock climbing evolved gradually from an alpine necessity to an athletic sport in its own right. As rock climbing matured, grading systems were created in order to more accurately compare relative difficulties of climbs. Over the years, both climbing techniques, and the equipment climbers use to advance the sport, have evolved in a steady fashion.

# Rock climbing basics
Handy definitions:
Protection: spring-loaded or static metal devices designed to be inserted into rock cracks or other irregular surfaces. Protection is placed as the climber ascends; the climber clips the rope into the protection. The protection works in tandem with the belayer to prevent the climber from hitting the ground in the event of a fall.
Belay:
Harness:
Overview:
Climbers usually work in pairs, with one climbing and the other belaying. In lead climbing, the belayer feeds rope to the lead climber through a belay device. The leader climbs up, occasionally placing protection or clipping preplaced bolted hangers, until the top is reached. The belayer is ready to "lock off" the rope if the leader falls.
Both climbers attach the rope to their climbing harness, usually tying into their harness with a figure-eight knot or double bowline knot. The leader either places protection or clips into permanent protection already attached to the rock. In traditional climbing, the protection is removable. Usually nuts or Spring-loaded camming device (often referred to as "cams" or "friends") are set in cracks in the rock (although pitons are sometimes used). In sport climbing the protection is metal loops called hangers. Hangers are secured to the rock with either expanding masonry bolts taken from the construction industry, or by placing glue-in bolt systems. In ice climbing the protection is Ice Screw or similar devices hammered or screwed into the ice by the leader, and removed by the second climber.
The lead climber typically connects the rope to the protection with carabiners or quickdraws. If the lead climber falls, he will fall twice the length of the rope out from the last protection point, plus rope stretch (typically 5% to 8% of the rope out), plus slack. If any of the gear breaks or pulls out of the rock or if the belayer fails to lock off the belay device immediately, the fall will be significantly longer. Thus if a climber is 2 meters above the last protection he will fall 2 meters to the protection, 2 meters below the protection, plus slack and rope stretch, for a total fall of over 4 meters.
If the leader falls, the belayer arrests the rope. This is achieved by running the rope through a belay device attached to the belayer's harness. The belay device runs the rope through a series of sharp curves that, when operated properly, greatly increase the friction and stop the rope from running.  Some of the more popular types of belay devices are the ATC Belay Device, the Figure 8 and various auto-locking belay devices such as the Petzl Gri-Gri
At the top of the pitch, the leader sets up a secure anchor system, also called a belay, from where he can belay as his partner climbs. The second climber removes the gear from the rock (traditional climbing) or removes the quickdraw from the bolted hanger (sport climbing). Both climbers are now at the top of the pitch with all their equipment. Note that the second is protected from above while climbing, but the leader is not, so being the leader is more challenging and dangerous.  After completing their climb, with both climbers at the top of the pitch, they must eventually rappel or otherwise descend the climb in order to return to their starting point.
Occasionally, climbers may decide to "move together", a risky but speedy technique also called simul-climbing, in which both leader and second move at the same time without stopping to belay. The leader - approximately a rope length above the second - usually places multiple pieces of protection as he climbs so that the weight of the second climber might arrest a possible leader's fall. Should it be the second climber to fall, however, the leader may be pulled from his holds, with potentially unpleasant results.

# Types of rock climbing
Rock climbing may be divided into two broad categories: free climbing and aid climbing.
- Free climbing requires the climber use only natural features of the rock formation.
- Aid climbing involves using artificial devices placed in the rock to support all or part of the climber's body weight, and is normally practised on rock formations that lack necessary natural features suitable for free climbing.
Other kinds of climbing :
- Lead climbing is a technique where the lead climber or leader ties to one end of a rope and is belayed by their partner. The climber then ascends the route, periodically placing protection for safety in the event of a fall.
- Traditional lead climbing, or "Trad lead climbing", uses mostly removable protection, but also may employ fixed bolts if these were put in on the lead. It is a type of Lead climbing, so the climbing team begins at the bottom of a climb and ascends to the top, with the leader placing protective devices in the rock as he or she climbs. If the climber falls, he/she does not rest on the rope and instead lowers to a stance or the ground to start over. This approach of protection and climbing progress emphasizes the exploratory aspect of the sport and requires a certain amount of boldness. Trad leading is considered by many to be the cleanest style, as the climber to follow the leader, called the second, or sometimes cleaner, removes the protective devices (except any fixed bolts put in on lead) and leaves but marginal traces (if any at all) of their passage.
- Sport lead climbing is a type of lead climbing which involves the use of pre-placed, permanent bolts for protection. This frees the leader from carrying excessive gear - he/she merely clips in to the bolts with quickdraws. However, permanent protective devices, like bolts and fixed pitons, are subject to dislodgment or decay over time and thus may become an insidious hazard for a leader. In case of a fall, sport climbers often rest on the rope before beginning again. Hard sport climbs often entail many falls and rests before being completed without falls and rests. In contrast, traditional style employs no rests on the rope, starting over after falls without rope tension and generally a minimal number of falls.
- Top rope climbing, or top-roping, involves suspending a rope from an anchor located at the top of a short climb. The climber is then safeguarded by his belayer who holds the rope either at the top of the route or at the base of the climb.  This is distinct from lead climbing where the climber places protection as they ascend.
- Bouldering may be described as climbing short, severe routes on boulders or small outcrops. While safety ropes from above are occasionally used, most boulderers feel that the most ethical form of protection is a bouldering mat or pad similar to those used by gymnasts. In addition, other climbers standing on the ground may "spot" the boulderer, to help break his or her fall.
- Indoor climbing is a form of climbing that can involve bouldering, top roping, and leading in an indoor environment on wood or plastic holds.  For most it will be the easiest way to begin the sport.
- Free solo climbing: Usually describes free climbing without a rope or other protective gear. Free solo climbing is distinguished from solo climbing where a climber progressing alone uses a rope and protection devices including a self belay system.

# Rappelling / Abseiling
Rappelling (USA usage - French, meaning "return") or abseiling (UK and Ireland usage - German, meaning "down rope") is a common method for returning to the bottom of a completed climb. On climbs where rappelling is impractical or disallowed the alternative is usually either walking out from the top of the climb, or down-climbing.

# Gear and Equipment

# Grades
Climbing communities in many countries, as well as individual regions, have developed their own climbing rating systems.  Ratings are a method to communicate or record the consensus difficulty of climbs. See the main article for details of the various systems, and a comparison chart.

# Indoor Climbing Walls
In recent years, indoor climbing walls, basically artificial cliffs, have become quite popular. Climbing walls are often used to teach beginners because the risk of injury or fatal accident is greatly reduced. They are also used by experienced climbers who hone their skills without the need to travel to rock formations.

# Criticism
Although most climbers adhere to "minimal impact" and "leave no trace" practices, rock climbing is sometimes damaging to the environment.  However, the impact is often less than other outdoor recreations such as hiking, due in part to the smaller numbers participating in climbing compared to other outdoor sports. Common environmental damages include: soil erosion, litter, abandoned bolts and ropes, human excrement, introduction of foreign plants through seeds on shoes and clothing, and damage to native plant species.
Clean climbing is a style of rock climbing which seeks to minimize some of the negative side-effects of climbing.