The Dobrogea is the Black Sea coast of Romania. It starts in the north at the Danube, which is the border to Moldavia. This northern part are the marshes of the Danube delta. To the south follows hillcountry with an average altitude of about 200-300 m asl.

Huge parts of the area are covered by limestones and karstified. The parts with higher altitude, the Măcin Mountains, are the oldest mountains in Romania, formed by the Hercynian orogeny, during the Carboniferous and Permian. The predominant rock is granite, which is eroded in the typical rounded form of exfoliation, creating structures which resemble the ruins of castles. The highest peak is called Ṭuṭuiatu or Greci (467 m asl).

Although this is probably the largest karst area in Romania, there are no caves open to the public so far. The only cave we listed, is also closed, but of immense importance to science.