Underneath the sleepy stone villages of the Slovenian Karst, a river called the Reka plunges into the earth and carves one of the largest underground canyons known anywhere. The Škocjan Caves, a UNESCO site since 1986, are the reason the word karst became the scientific name for this kind of limestone landscape everywhere in the world. Inside, a narrow footbridge spans the Reka gorge far above the roaring water, the chamber walls disappear into darkness, and the scale is so huge that your mind struggles to accept it is all underground.
The guided tour takes a couple of hours and is well worth it; the temperature in the caves stays cool all year, so bring a layer even on a hot day, and the paths are damp and steep in places. Outside, the trail around the collapsed dolines of Velika and Mala dolina shows where the cave roof fell in long ago, and the tiny village of Škocjan clings to the rock above them. Swallows, bats and the sound of running water fill the air.
The Karst plateau is a lovely place to ride. Narrow roads connect stone villages through oak scrub, sumac that turns scarlet in autumn, and dry stone walls, with vineyards growing the dark local Teran grape and smokehouses curing pršut ham. Corners are tight, surfaces mostly good, traffic light away from the main roads, and the views stretch toward the Adriatic around Trieste. Be warned about the bora, the cold northeasterly wind that can blow here with frightening force, especially in winter, rocking a bike sideways on exposed stretches. Spring and autumn are perfect, summer is warm but rarely brutal up here.
Divača, three kilometres away, is a small town with fuel, a supermarket and simple places to eat; Sežana, about eleven kilometres away, is larger and has more choice. The motorway between Ljubljana and the coast passes close by, and remember that Slovenian motorways require a vignette, motorbikes included. Lipica, home of the Lipizzaner horses, is a short ride away, and so is the Vilenica cave, one of the oldest show caves in Europe. Finish the day in a family farm tavern with a glass of Teran and a plate of pršut and cheese, and you will understand why people who come here once usually return.