Rockcrawling

Rock crawling is an extreme form of off-road driving. Participants use vehicles anywhere from stock to highly modified to overcome obstacles (usually rocks). In rock crawling, drivers drive highly modified four-wheel drive vehicles such as trucks, Jeeps, and "buggies" over very harsh terrain. Driving locations include boulders, mountain foothills, rock piles, mountain trails, etc.
Rock crawling is about slow-speed, careful and precise driving, and high torque generated through large gear reductions in the vehicle's drivetrain. Rock crawlers often drive up, down and across obstacles that would appear impassable. Most vehicles used to rock climb are primarily 4x4s.
Rock crawling competitions range from local events to national series. A rock crawling competition consists of obstacle courses that are about long. Each obstacle is set up with gates, similar to a ski course. Usually a spotter (person who guides the driver) helps the driver through hard obstacles. Spotters may also use a rope to help prevent a vehicle from tipping over. 
Rock crawling basics.
The vehicles.
Vehicles commonly used include Jeep, Nissan Patrol, Toyota Land Cruiser, Land Rover, Ford Bronco, Suzuki Samurai, International Harvester Scout. Also, vehicles like the Mercedes Unimog due to its portal axles and greatly increased ground clearance. These vehicles are outfitted with custom parts. Power is usually not an issue, as rock crawlers typically lower their gear ratios in order to drive more slowly over obstacles without stalling the engine. These custom parts can include:
Oversized, low-pressure, knobby, mud-terrain tires are used. Most vehicles have a low-geared transfer case to make the most torque in the low speeds used for rock crawling. Suspension-wise, rock crawling vehicles sometimes have aftermarket lift kits installed, raising the chassis and increasing suspension flexibility. Highly modified rock crawling vehicles are less suitable for driving on roads and highways.
Building a dedicated rock crawler can cost a lot of money. For rock crawling competitions, getting a sponsor can help to cover some of these costs.