Smolyan

The limestone here is cut by narrow gorges where the rock rises vertically on both sides of a road barely wide enough for two cars, and the most dramatic of them ends at a cave where a river disappears underground. Inside, the water falls into a chamber large enough to swallow the noise, and the outflow emerges downstream having passed through a system nobody has been able to map — objects put into the water have never been recovered, which is the sort of fact that sounds invented and is not. A second cave nearby is the opposite proposition, a long walkable passage with formations and lighting. Between them they are the best few hours in the province.

The Rhodopes were never emptied the way the high ranges were, so the settlements here are working places rather than museum pieces — stone ground floors with timber above, roofs of heavy split slate, and lanes that were laid out for animals. Several villages have kept enough intact fabric to be protected, and the difference between them and the preserved towns further north is that these were never restored for visitors. Accommodation is family guesthouses, food is what the household cooks, and the region's reputation for hospitality is not a tourism slogan.

The Rhodopes carry a vocal tradition that is genuinely distinctive — open-throated, close-harmony, with a scale and an ornamentation that sound strange to an ear trained on western European music, and it is sung by ordinary people at ordinary occasions rather than performed. It travelled internationally in the late twentieth century through recordings and has been widely borrowed since. Hearing it in the province means arranging it through a guesthouse or catching a village celebration, and it is worth asking about rather than expecting to stumble into.

There is no fast way through the Rhodopes and that is the point. The roads follow valleys and ridgelines, distances are slow, and the province is best treated as somewhere to spend time rather than cross. The main approach is from the north, up from the plain past the great monastery; roads also run south to the Greek border crossings, which makes the range a plausible route between the two countries for anyone with time. In winter the higher roads carry snow and the small ski areas around the provincial capital open.