The essence of a modern via ferrata is a steel cable which runs along the route and is periodically (every 1 to 10 metres (3.3 to 32.8 ft)) fixed to the rock. Using a via ferrata kit, climbers can secure themselves to the cable, limiting any fall. The cable can also be used as aid to climbing, and additional climbing aids, such as iron rungs (stemples), pegs, carved steps and even ladders and bridges are often provided. Thus via ferratas allow otherwise dangerous routes to be undertaken without the risks associated with unprotected scrambling and climbing or the need for climbing equipment such as ropes. They offer the relatively inexperienced a means of enjoying dramatic positions and accessing difficult peaks, normally the preserve of the serious mountaineer; although, as there is a need for some equipment, a good head for heights and basic technique, the via ferrata can be seen as a distinct step up from ordinary mountain walking. Conversely, the modest equipment requirements, ability to do them solo, and potential to cover a lot of ground, mean that via ferratas can also appeal to more experienced climbers.

from Wikipedia