Belchen system
The Belchen system comprises five mountains with the name Belchen around the tripoint of Germany, France, and Switzerland that may have been used by the Celts as a solar calendar. The term is an extension of the Belchen triangle. The mountains are:
- Belchen, or Black Forest Belchen
- Belchenflue, or Swiss Belchen
- Ballon d'Alsace, or Alsatian Belchen
- Grand Ballon, or Great Belchen
- Petit Ballon, or Little Belchen