The Eye, Glacial lake in Rila Mountains, Bulgaria.

The Eye is a glacial lake in the Rila Mountains characterized by its oval shape and exceptional depth of about 37.5 meters. It sits at approximately 2,440 meters elevation and ranks as Bulgaria's deepest cirque lake, cradled by dramatic rocky slopes.

The lake appears in records under three names: Okoto, Heart, and the older Chanak ghol. On 25 October 2005 Bulgarian divers Rumen Zhelezarov and cameraman Vladimir Vekov made the first dive in Bulgarian diving history here, reaching the bottom at 37.7 m and finding the depth had grown over the years. They gave sediment and water samples to Sofia University's hydrobiology department, where Yana Topalova's team found the water exceptionally pure; Vekov's underwater film went to Rila National Park.

Local shepherds named this lake for its oval shape, which resembles an eye when viewed from above. This comparison remains embedded in how people today describe and experience the place.

Ice covers the lake from October through June with layers reaching up to two meters thick, while summer offers the most favorable conditions for visits. Expect rapid weather changes at this elevation and prepare with sturdy footwear suitable for mountain terrain.

On 25 October 2005, divers Rumen Zhelezarov and cameraman Vladimir Vekov made Bulgaria's first dive to the lake's deepest point, 37.7 m, and found the depth increasing over the years. They gave sediment and water samples to Sofia University's hydrobiology department, where Yana Topalova's team found the water exceptionally pure. Vekov filmed a documentary and donated it to Rila National Park.