Borçka Karagöl is a small lake lying on the rubble of an old landslide. Sometime in the 1800s, in a year nobody wrote down, a mass of rock broke off the ridge between Karaşalvar and Verketil on the northwestern flank of the Karçal range. It ran three and a half kilometres down the valley and lost a thousand metres of height on the way. The usual account says the debris dammed the Savgule stream and the water backed up behind it. The geographers who surveyed the slide read it differently: they found the water standing in two hollows on the rubble itself, and the lake covers only a few percent of the landslide's bulk. What is left either way is small and dark — about 50,000 square metres of water at 1,480 metres of altitude, and some 25 metres deep at its deepest point. Nordmann fir, oriental spruce and beech grow tight to the shore, and their reflection makes the surface look almost black. That is where the name comes from: kara göl means black lake.
A wooden walkway runs the whole way round the shore. In the first hour of daylight mist lies on the water and the forest is reflected so sharply that the real bank and its reflection are hard to tell apart. Clear mornings are rare, because the sky above Borçka is overcast roughly 170 days a year, so that mirror is a matter of luck rather than planning. From mid-October the beeches turn yellow and red against the black-green conifers and the whole basin runs with colour. By February the lake carries a crust of ice, and avalanches off Sakugune Tepe drag tonnes of timber down into it. It has been a nature park since 2002, and it now has a quieter problem: the two streams that feed the lake also wash silt into it and are slowly filling the basin, so weirs were built upstream to trap the sediment.