A key element of Kranj's magnificent medieval skyline and quite literally an inseparable part of the town (as the complex's lower section forms part of the defensive walls), Khislstein Castle derives both its name and Renaissance appearance from its 16th-century owner Janez Khisl. Historical records show that other fortifications were built on the same site as early as the 5th century, while excavations of the castle's foundations have unearthed artefacts going all the way back to late Antiquity. More recently the castle and its grounds were extensively renovated in 2012, when the open-air summer theatre was built and the Museum of Gorenjska's central exhibition was opened on the premises.

Titled Beautiful Gorenjska, the comprehensive and extremely well-presented exhibition leads visitors on a journey from the geological formation of the region millions of years ago, through prehistoric settlements, the arrival of Slavic tribes, development of Slovenes as a distinct people, growth during the medieval and renaissance periods, and concludes with modern Slovenia's accession to the European Union. Special emphasis is given to several other important areas such as the ethnology of rural life in the region, including both the hardships faced and social triumphs, the notable individuals of the 19th century, both World Wars and the Yugoslav era. The space of the castle's interior is used to maximum effect, and some interesting and novel curatorial approaches make a visit here both fascinating and informative. As such, the museum is great place to begin a first trip to the region.