The Église Saint-Jean-Baptiste, standing at the southern end of the Vieux Port, is Bastia's principal church and one of the most impressive baroque churches on the island. The current building dates from the late 17th century, though it was substantially modified and extended through the 18th and 19th centuries. The twin belltowers that define the Bastia skyline as seen from the sea were added in 1852.
The interior is richly decorated in the Italian baroque manner: painted ceilings, gilded altars, and side chapels filled with dark oil paintings. The most notable piece is the high altar in polychrome marble. The church gives onto the Vieux Port on one side and the narrow lanes of Terra Vecchia on the other. Mass is held daily, and the church is open to visitors outside services.