The Karst Plateau in the Slovene Littoral gave its name to karst, a landscape shaped by water dissolving the carbonate bedrock, forming caves. The best-known caves are Postojna Cave and the UNESCO-listed Škocjan Caves. The region of Slovenian Istria meets the Adriatic Sea, where the most important historical monument is the Venetian Gothic Mediterranean town of Piran while the settlement of Portorož attracts crowds in summer.