Flanked by cliffs of alternating red and white stone, the River Iskar meanders in spectacular fashion through a particularly deep valley. The first gorge is about 8km long. Its strange "foliated" crest and its tunnels dug through the rock greatly contribute to the picturesque of the site. Beyond a more industrialised section, one reaches another gorge, lined with sheer rock faces and jaggered rocks. From Svoge onwards, the valley widens and becomes more pleasant until it reaches Sofia.