The Alpenvorland (Alpine Foreland) is the region between the Swabian Alb or the Danube and the Alps, from Lake Constance in the west to the Austrian border in the east. This natural area is flat and has mainly ground moraine and some terminal moraines. During the uplift of the Alps and the South German Scarplands, this area was lowered and filled with up to 3.5 kilometres of sedimentary rock over millions of years. The large natural region also represents a geological unit, known as the Molasse or Molasse Basin. However, the name has nothing to do with syrup (molasses). The geological unit extends in the west to France and Switzerland as far as Lake Geneva, and in the east to Austria as far as Vienna. In total, the structure is around 1,000 kilometres long. In the course of time, the basin was filled with both seawater and a huge lake, which is why it is referred to as either freshwater molasse or marine molasse. Remnants of this period can also be found in the form of fossilized cliffs on the southern edge of the Swabian Alb as well as boreholes drilled by shells and the turritellae of the Erminger Turritellenplatte.
However, the glaciers of the Ice Age, which came from the Alps and covered the entire area as far as the Danube, shaped the landscape of today. The advance phases are documented in various terminal moraines and were categorized early on into four large glacials. Here in the south of Germany, these are named after the tributaries of the Danube, Günz, Mindel, Riß and Würm. The glaciers also shaped the landscape as they melted, and the Urdonau created the unique Blau and Schmiech valleys.
The region hardly has any subterranean features, as it was never elevated high enough to be karstified. In other words, underground drainage is largely absent. There is a rather controversial opinion to the contrary, but no caves have yet been found, and if they exist, they are deep underground and filled with hot groundwater. The sights are therefore mostly subterranea and mines, small springs and gorges.