The subgroup of the Tannheim Mountains (Tannheimer Berge) was still counted in the first half of the last century as an independent mountain range in the Northern Limestone Alps. In places the name Vils Alps (Vilser Alpen) was common. Only later was it considered part of the Allgäu Alps. The highest mountain is the Köllenspitze, NN. The broad Tannheim valley clearly separates the Tannheim Mountains from the rest of the Allgäu Alps. There are geological differences too. Whilst large areas of the Allgäu Alps are made of brittle main dolomite or Jurassic rocks of the Allgäu Beds which must also be carefully handled, Wetterstein limestone, a reef limestone, dominates the main part of the Tannheim Mountains. This is a solid rock. As a result, the Tannheim Mountains, with their well known peaks, the Rote Flüh, Gimpel, Köllenspitze and Gehrenspitze, are a renowned climbing area. The subrange is also popular with mountain hikers. Especially in the early summer, when the main chain of the Allgäu Alps is still snow-covered, there are many paths here that are already passable.