Set within a lush park on the natural defensive prominence of Lossimäed, the scant-yet-evocative remains of Viljandi's powerful castle form a picturesque set of ruins with sweeping views over the valley and lake below. Built in 1224 by the German Knights of the Sword on a series of three small hills divided by ravines, it replaced an Estonian hill fort that had stood here since the 9th century. It finally fell into disrepair after the 17th-century Polish-Swedish wars.
Only perilously decayed sections of wall and crumbling foundations remain but you get a sense of the castle's scale, and there are interesting display panels describing its layout. One of the approaches to the fortress is spanned by an elegant 50m suspension footbridge, which was built in 1879 for another set of castle ruins at Tarvastu and was only moved to this site in 1931.
A small cemetery to the rear of the castle park is the final resting place of German soldiers killed here during WWII.