For a relatively small country, almost
111,000sq km (43,000sq miles), Bulgaria's
topography is extremely varied.
Almost 30 per cent of the country's landmass is mountains, with more than 30 peaks over 2,000m (6,500ft). These, and their corresponding valleys, have played a major part in the moulding of Bulgarian lifestyle and Bulgarian character - a self-reliant population of insular mountain folk and arable farmers in the leas and meadows of the
lowlands. The Stara Planina mountains divide the country and shape the weather. They halt the southerly track of the harsh winter steppe winds and interrupt the northerly progress of very dry heat from the Mediterranean in summer, affecting the native flora and fauna and the development of agriculture throughout the country. Each mountain range has its own distinct appeal. The alpine peaks of the Pirin are in marked contrast to the karst (eroded limestone producing sinkholes, fissures and ridges) of the Blue Rocks and the Ropotamo basin or the gently rounded knolls of the Sredna Gora. Bulgaria is equally rich in underground landscapes. Some 4,300 caves and caverns constitute a veritable hidden world that's played an important role in Bulgarian history — protecting its population, its religion and its national heritage.