Commenced from the 9th century and reaching its peak as a royal residence in the 11th century, this hulking fortress looms over the town from steep Spas hill. Its strategic importance is well demonstrated by the extraordinary views it offers over the valley to the mountains of Bosnia and Hercegovina.
When the Croatian kings fell, Knin was battered by a series of invaders until the Ottomans snatched it in 1522. Later, Venice swept in (note the republic's winged-lion emblem over the main gate), followed by Austria, France and then Austria again. Much of the present structure dates from the 17th and 18th centuries.