The steep road to Kalin dam

Kalin dam is known* as the highest dam on the Balkans at 2400 m ASL. Built in 1948, it supplies the Kalin pumping storage HPP, situated some 800 m lower. The 16 km long concrete road overcomes 1700 m of difference in height with average slope of 11%. Aldough, the slope in the first half of the road is predominantly 9% and in the second - up to 18%.
*In fact, the adjacent small dam "Little Kalin" is a few meters higher and is the actual highest one. It constantly overflows to the main dam through a short tunnel.