Postojna is a small town on the Karst plateau of south-western Slovenia, and almost everyone who comes here has one purpose: the cave. The Postojna Cave system, carved by the Pivka river through limestone, runs for more than twenty kilometres, and part of it is visited by an electric train that carries you deep into the mountain before you walk through halls of stalactites and pale columns. It has been a tourist attraction since the early nineteenth century, one of the oldest in Europe. The temperature inside hovers around ten degrees all year, so bring a warm layer even if you arrive in a heat wave.
In the dark pools of the cave lives the olm, a pale, blind salamander that can survive for years without food. Locals call it the human fish because of its skin colour, and in the old days people believed it to be a baby dragon, a story the Slovenes seem to enjoy. A few kilometres away, Predjama Castle clings to the mouth of a cave in a sheer cliff, the stronghold of a robber knight, Erazem, who is said to have held off a siege for a long time thanks to a secret passage.
For riding, this is limestone country, with rolling forested hills, sinkholes and plateaus. The roads to the Vipava valley and the coast are scenic and fun, with sharp bends, though the surface can be slippery in wet weather. The wind called the bora blasts down from the hills in winter and can be fierce, particularly on the motorway near Razdrto and on exposed viaducts. Check the forecast and keep a firm grip if it is gusting.
Slovenia requires an electronic vignette for motorways. Fuel is available in Postojna itself, a town of about nine thousand, which has stations by the main road and supermarkets. Order pršut, the dry-cured Karst ham, and a glass of teran, a tart red wine from the region, before you head down to the sea.