The Stations of the Cross, also known as the Way of the Cross or Via Crucis, commemorate Jesus’s passion and death on the cross. There are 14 stations that each depict a moment on his journey to Calvary, usually through sacred art, prayers, and reflections. The practice began as pious pilgrims traced his path through Jerusalem on the Via Dolorosa.
Later, for the many who wanted to pass along the same route, but could not make the trip to Jerusalem, a practice developed that eventually took the form of the fourteen stations currently found in almost every church throughout the world. Similarly, the 150 Hail Marys that were recited for the rosary were an adaptation of the medieval monastic practice of reciting the 150 psalms in the Psalter. – USCCB
Taken in the former sense, the Stations may be of stone, wood, or metal, sculptured or carved, or they may be merely paintings or engravings. Some Stations are valuable works of art, as those, for instance, in Antwerp cathedral, which have been much copied elsewhere. They are usually ranged at intervals around the walls of a church, though sometimes they are to be found in the open air, especially on roads leading to a church or shrine. In monasteries they are often placed in the cloisters.