A basilica is a large and important church building, often characterized by its architectural style and historical significance. Traditionally, basilicas have a rectangular shape, with a central nave flanked by aisles, and they often feature a raised platform for the altar. Many basilicas are associated with the Roman Catholic Church and serve as important places of worship and pilgrimage. The term "basilica" can also refer to a specific designation given by the Pope to certain churches that hold special significance. These churches may contain relics or be located in historically important areas. Notable examples include St. Peter's Basilica in Vatican City and Basilica of the National Shrine of the Immaculate Conception in Washington, D.C..