The Stations of the Cross is also called "Via Dolorosa", "Via Crucis", or the "Way of the Cross". The devotion can be traced as originally coming from pilgrimages in the Jerusalem, where people would travel the path of Christ's Passion, starting from the house of Pontius Pilate, to the crucifixion site at Calvary, stopping at holy sites along the way. It is said that the Virgin Mary visited the path of Christ's passion daily.

Because of the difficulty of traveling to the Holy Land, clergymen in various locations around Europe built shrines of certain holy places in Jerusalem, allowing people to make mini pilgrimages. By the 15th century, the devotion had evolved more or less to its modern form, where people pray at each "station" -- an artisitc depiction of an event in Jesus's Passion.

The number of stations have not always been the way it is now. It has varied widely throught the years, but in 1731 Pope Clement XII fixed the number of stations to fourteen. However, many churches nowadays add a fifteenth station, "Jesus is raised from the dead."

The devotion itself requires only that a person stops at every station, and meditate. It may be done by a single person, or with a group. Though the devotion can be done any time, it has come to be associated with Lent, and in particular Good Friday. Before each station, it is customary to say:

We adore you, O Christ, and we bless you,
because by your holy cross,
you have redeemed the world.

Often at the station, a commentary by some holy person or writer is read. After each station, an Our Father, Hail Mary, and Glory Be may be said.

Representations of the stations vary widely, there can be simple crosses for each station, or elaborate artwork. Most Roman Catholic churches have the stations of the cross depicted around their walls. Typically these are paintings, or reliefs of wood or stone. The stations are often placed outdoors as well. Many sculptures depicting the stations line the paths to monasteries and seminaries.

Whatever the representation, the practice encourages people to reflect on how Christ's suffering saved us from our sins.


Reference and more information:
http://www.newadvent.org/cathen/15569a.htm