The largest fortress in Slovenia, this castle is perched on a 407m-high escarpment about 2km southeast of the Old Town; the walk up via a footpath from Cesta na Grad takes about half an hour. The castle was originally built in the early 13th century and went through several transformations, especially under the Counts of Celje in the 14th and 15th centuries. A large portion of the walls remain intact and have been restored, including 23m-high Frederick's Tower (Friderikov Stolp).
When the castle lost its strategic importance in the 15th century it was left to deteriorate, and subsequent owners used the stone blocks to build other structures, including parts of the Princes' Palace and the Old Counts' Mansion. Due to this, there's not much inside, though concerts are staged and medieval-themed events take place in the warmer months.