The mountain emerged as a result of volcanic activity and has been subsequently shaped by the slow folding of the granite rock layers and a series of gradual uplifts of the area. It appears dome shaped at first sight, but the mountain, 19 km long by 17 km wide, actually consists of concentric denudational plateaus rising in tiers one above the other. Vitosha is separated into four main parts whose main ridges gather at a crown known as Cherni Vrah (Black Peak). This is the highest point of the mountain at 2290 m and is one of 10 peaks of Vitosha over 2000 m in height. It is the highest massif of Srednogorie mountain chain system, together with Sredna gora, Plana (mountain), Lyulin Mountain, Greben (mountain), Viskyar Mountain, etc. They all are a result of the folding of the earth layers through the Mesozoic, causing also magma sheet-like intrusion (or concordant pluton) that has been injected between layers of sedimentary rock. The lacolithic domed form of Vitosha is a typical example.