Göygöl was made in a single night. In 1139 an earthquake of roughly magnitude 7.7 destroyed the nearby city of Ganja and tore the flank off Mount Kapaz; the rock slid into the valley, dammed the Ağsu river, and the drowned gorge filled with water. Six more lakes formed in the same collapse, Maralgöl among them, but Göygöl is the one Azerbaijanis mean when they say Blue Lake — which is exactly what the name says. The mountain that made it still rises 3,066 metres directly behind the water, and the dam holding the lake in is nothing but the shattered stone that fell. It sits at about 1,550 metres in the Lesser Caucasus, runs close to three kilometres end to end, and drops more than ninety metres deep. On a still day you can watch the bottom fall away eight to ten metres below you.
Most people arrive expecting pine. Pines do stand around the mountain village of Hacıkənd on the road up, but the shore itself is beech, hornbeam and oak — which is why the whole bowl turns gold and rust through October and then repeats the colours upside down in the water. This has been protected land since 1925, when Azerbaijan created its first nature reserve here; the national park grew out of it in 2008 and now covers 12,755 hectares, almost all of it forest. You will not swim: the ban is absolute, and it is a large part of why the water still looks the way it does. What you get instead is a marked shore path, a longer climb through the beeches to Maralgöl, and cold, still air that carries every sound across the water.