Within the grounds of Prague Castle, the Roman Catholic St. Vitus Cathedral (Katedrala St. Vita) is the Czech Republic’s largest and most important Christian church. Seat of the Archbishop of Prague, it’s also home to the tombs of numerous saints and three Bohemian kings. Founded on the site of a Romanesque rotunda built in 925 AD, the cathedral was started in 1344 and took more than 525 years to complete, resulting in a mix of modern Neo-Gothic and 14th-century Gothic styles, along with Baroque and Renaissance influences.

Highlights include stunning stained glass windows depicting the Holy Trinity, a mosaic from 1370 (The Last Judgment), and the St. Wenceslas Chapel (Svatovaclavska kaple) with its spectacular jewel-encrusted altar with more than 1,300 precious stones. Also of note, although rarely displayed, are the Czech crown jewels (on average, they’re exhibited just once every eight years). Be sure to make the climb up the cathedral’s 97-meter main tower for splendid views over Prague.