The Church of St. Helena was built in the 7th century at the latest, making it the oldest building in Kastav. Throughout history, it has often been redecorated and reconstructed. During the 18th century, it was decorated in the Baroque style with a rich interior in which there is a choir bench and kneeler, a baptistery, and candle holders from the 17th century. Above the pillars of the main and side naves are interesting drawings of the Ten Commandments. Next to the church is an 18th-century bell tower 32 meters high. The church is located on a hill 377 meters above sea level and offers a beautiful view of the entire Kvarner Bay and Mount Ucka.