These regions have different geographical structures. Whilst the "Mostviertel" is dominated by the foothills of the Limestone Alps with mountains up to high, most of the "Waldviertel" is a granite plateau. The hilly "Weinviertel" lies to the northeast, descends to the plains of Marchfeld in the east of the state, and is separated by the Danube from the Vienna Basin to the south, which in turn is separated from the Vienna Woods by a line of thermal springs (the "Thermenlinie") running north to south.