Wawel Castle in Krakow - Poland

Wawel is an architectural complex erected over many centuries atop a limestone outcrop on the left bank of the Vistula River in Krakow, Poland, at an altitude of 228 metres above the sea level. The Royal Castle with an armoury and the Cathedral are situated on the hill. The limestone Wawel is strongly karsted and abounds in caves (e.g. the Dragon's Den - Smocza Jama).