You don't have to be religious to appreciate the peaceful atmosphere of St. Peters Cathedral. Ask when the next service starts or when it's open for general viewing.
You'll soon see why this Dago principal church is a hit with travelers. If you're looking for more to explore, Paris Van Java Mall, Trans Studio Bandung, and Cihampelas Walk are in the area as well. They won't take you very long to reach from St. Peter's Cathedral.