Adventure tourism involves exploration or travel to remote, exotic and possibly hostile areas. Adventure tourism is rapidly growing in popularity, as tourists seek different kinds of vacations. Adventure tourism gains much of its excitement by allowing its participants to step outside of their comfort zone. This may be from experiencing culture shock or through the performance of acts, that require significant effort and involve some degree of risk (real or perceived) and/or physical danger(See extreme sports). This may include activities such as mountaineering, trekking, bungee jumping, mountain biking, rafting, zip-lining, paragliding, and rock climbing. Some obscure forms of adventure travel include disaster and ghetto tourism.