Gorlo Canyon

The Arda is the longest river in the Rhodopes, and 17 km below its source it does something strange: it vanishes into the marble. Over thousands of years the water has cut a corridor through solid rock, and at one point the walls close to just over two metres apart while the river beneath runs more than four and a half metres deep and turns almost black. There is no path along the edge. The only way through is the way the water goes.

You take to a boat and glide into the gap. The light overhead narrows to a ribbon, the sound falls away to the dip of the oar, and for a few minutes the canyon has you entirely. Those minutes end before you are ready for them to, and you step back onto the bank with the feeling of a story left mid-sentence, one only the canyon can finish. The crossing is the closing note of the day tours from Mogilitsa, after the Nadarska Cave and either Rufinka's grave or the Kiselchovo waterfalls.