This mediaeval noble town is at the top of the southern slope of the Medvednica Mountain near to Zagreb. Medvedgrad is the most important example of medieval civil architecture in Zagreb. The bishop of Zagreb built the fortress in the 13th century, with the permission of King Bela IV. The fortress, erected near the western border of the Hungarian-Croatian state, was of great strategic importance. The double-ringed walls of impressive proportions, massive towers and heavily defended entrances made the fortress virtually impenetrable. Access to it was possible only from the north. Between the outer and inner walls of the fortress there is a long and narrow funnel-shaped corridor, with gateways at both ends to stop invaders. This remarkable heritage site has been researched and restored by the Croatian Restoration Institute.