Biking from Sofia to Svoge. This route completely avoids the road in the Iskar Valley at the cost of some denivelation. After the Village of Balsha there are several steep sections until you gain height, you may be forced to push the bike from time to time. Descending to Svoge is even steeper. Dirt tracks and slopes require good technical skills. Buying some water in Balsha is a very good idea.