Cathedral of St. Nicholas is a Baroque Cathedral was built in the XVIII century by the Italian architect Andrea del Pozzo on the site of the ancient Church of the XIII century. The interiors of the Cathedral are decorated by Italian craftsmen, the altar, the Bishop made famous Slovenian artist and architect Th. Plecnik, and murals painted by Giulio Qualia. The dome of the Cathedral designed by architect Gregor Macek was added later, and is painted in the nineteenth century by Matei Langsam.

Special attention deserves the doors of the Cathedral, on which modern Slovenian sculpture, Mirsad Begic engraved picture of the history of the Ljubljana diocese, on the occasion of its creation to the visit to the capital of Slovenia Pope John Paul II in 1996.