The Karst Plateau (Kras)

Every cave, sinkhole and vanishing river on the planet is described using vocabulary borrowed from this one plateau. Kras — Carso in Italian, Karst in German — is the limestone country between Ljubljana's basin and the Gulf of Trieste where 19th-century scientists first systematically described the landforms that water makes in soluble rock, and the region's name became the technical term worldwide. Slovenian words went with it: doline, polje and ponor are all standard in English-language geology.

It is also a landscape to travel through rather than merely study: red soil and pale stone walls, villages of heavy limestone houses, the bora wind coming off the Adriatic, and the food and drink that follow from it — dark teran wine grown on the iron-rich earth, and air-dried karst prosciutto hung in that wind. Škocjan, Vilenica and Lipica all sit on this plateau, which makes it the natural base for a caving trip.