A basilica is a large and important church building, often characterized by its grand architecture and historical significance. Originally, the term referred to a type of public building in ancient Rome, where people gathered for various activities. Over time, the Christian church adopted this style, leading to the construction of many famous basilicas, such as St. Peter's Basilica in Vatican City. Basilicas are typically designed with a long central nave, side aisles, and an apse at one end, where the altar is located. They often feature beautiful artwork, intricate mosaics, and impressive domes. Many basilicas are also designated as pilgrimage sites, attracting visitors from around the world.