The TRIGRAD GORGE ( Trigradsko zhdrelo ) is one of the most spectacular vistas in Bulgaria, its sheer walls overhanging the foaming River Trigradska, which disappears into a stupendous cave called the Devil's Throat ( Dyavolsko Gârlo ), accessible via a 150-metre-long tunnel at ground level (Wed-Sun 9am-5pm; hourly tours). The thunder of water is audible long before you sight a huge waterfall that vanishes into the bowels of the earth; objects swept into the cave are never seen again. As big as two cathedrals, the cave is traversed by crudely built stairways that can cut visitors fumbling for handholds in the gloom, as bats flit around the shaft of light entering through a mossy fissure overhead. On leaving, you can walk uphill to a viewing platform above the void where the Trigradska goes underground - in legend, the entrance to the underworld used by Orpheus - or scramble down beside the mouth of the road tunnel to find a placid pool at the bottom of the gorge, where the river reappears.

Fifteen minutes' walk beyond the Devil's Throat lies the sprawling village of TRIGRAD , whose mosque and tiny church reflect the relative size of its Muslim and Christian communities - and their closeness. The village was wealthy during Turkish times (when one landowner alone had 12,000 sheep), but is nowadays something of a sleepy backwater. The best place to stay in the village is at the unsigned Silivriak Hotel , on the highest street to the right above the main square (tel 03040/220; US$9-18). It's run by the custodian of the Devil's Throat cave, Kostadin ("Kotse") Hadzhesky, one of Bulgaria's foremost cavers and the person to ask about serious speleology. There are a few more small, family-run hotels in the village such as the Zdravets (tel 03040/391; US$9-18), which also runs organized excursions. Alternatively, you could stay at the Chairite (tel 03040/220; US$9-18), located in the protected lake district of the same name, 19km east of the village, a superb place to study the local flora and fauna.