A basilica is a large and important church building, often characterized by its architectural style and historical significance. Traditionally, it features a long central nave, side aisles, and an apse at one end. The term originally referred to a type of public building in ancient Rome, which was used for various civic purposes. In the Christian context, a basilica is often designated by the Pope and can be either major or minor. Major basilicas, like St. Peter's Basilica in Vatican City, hold special importance, while minor basilicas are significant but not as prominent.