In the centre of Istria, the small town of Pazin sits on the edge of a 130-metre vertical karst chasm — the Pazinčica river flows past the medieval castle and then disappears underground into a series of caves. The drop is dramatic and the castle that perches at its edge has been continuously occupied since the 9th century.
Today the castle houses the Ethnographic Museum of Istria, with displays on traditional rural life, plus the smaller town museum. The walk around the rim of the gorge is the real attraction — the path drops down into the chasm and out the other side, with cave entrances visible in the cliff. Combined with the museums, allow about three hours. Pazin is roughly central in Istria — well placed for combining with truffle country or the coastal towns.