View of ancient fortification on Havranok hill above Liptovska Mara lake in Liptov region at summer. Open-air museum of Havranok is an important archaeological site in northern Slovakia. This museum is located on hill where prehistoric Celtic settlement was located. Museum shows Celtic settlements and also medieval lifestyle of past centuries. This view portraits partially reconstructed wooden fortification with gate. Havranok settlement was important center of the Celts living in Slovakia. The Havranok site is proclaimed as the national cultural monument.