Krk Cathedral & Frankopan Castle

In the very corner of Krk's old town, where the walls meet the sea, an extraordinary two-building complex stacks 1,900 years of history on top of itself. The Cathedral of the Assumption stands directly on the foundations of a 5th-century Christian basilica, which in turn was built inside a 1st-century Roman thermal bath — you can descend into the cellar to see the original hypocaust heating pillars and fragments of Roman mosaic still in situ. Above ground, the three-aisled Romanesque nave of 1186 is supported by mismatched columns pillaged from earlier Roman buildings, each with a different capital. Immediately beside it stands the earlier basilica of St. Quirinus (5th century), and rising above both, the massive quadrangular keep of the Frankopan family — the medieval princes of Krk who ruled most of Kvarner from the 12th to the 15th century. Climb the keep for a superb view across the town's terracotta roofs to the Velebit coast. The complex hosts occasional summer choral concerts of exceptional acoustics thanks to the Romanesque proportions. Small joint-ticket admission covers the cathedral, the crypt with Roman remains, the St. Quirinus basilica and the castle keep — comfortably ninety minutes. Come early morning before the day-trippers from Baška and Malinska arrive.