The facade of a large church or cathedral, often referred to as the West Front, is generally designed to create a powerful impression on the approaching worshipper, demonstrating both the might of God, and the might of the institution that it represents. One of the best known and most typical of such facades is that of Notre Dame de Paris.
Central to the facade is the main portal, often flanked by additional doors. In the arch of the door, the tympanum, is often a significant piece of sculpture, most frequently Christ in Majesty and Judgment Day. If there is a central door jamb or a tremeu, then it frequently bears a statue of the Madonna and Child. There may be much other carving, often of figures in niches set into the mouldings around the portals, or in sculptural screens extending across the facade.
In the centre of the middle level of the facade, there is a large window, which in countries other than England and Belgium, is generally a rose window like that at Reims Cathedral. The gable above this is usually richly decorated with arcading or sculpture, or in the case of Italy, may be decorated, with the rest of the facade, with polychrome marble and mosaic, as at Orvieto Cathedral
The West Front of a French cathedral and many English, Spanish and German cathedrals generally has two towers, which, particularly in France, express an enormous diversity of form and decoration.[7][8] However, some German cathedrals have only one tower located in the middle of the facade (such as Freiburg Münster).
Source: http://en.wikipedia.org/wiki/Gothic_architecture
