The Albis is a moraine ridge left by the ancient glacier that carved out Lake Zurich.
At its northern point is the Uetliberg, the “house mountain” for the city of Zurich.
The ridge then runs roughly south, gradually rising, for some 20 km, passing through
Felsenegg, and the Albispass to end at the Albishorn. To the east the ridge drops
sharply as rather unstable cliffs into the valley of the river Sihl and to the west,
it slopes more gradually as farmland into the valley of the Reppisch. Along the
top of the ridge, which is quite narrow in laces, there is a gentle path which has
been populated since 2000 with the Planetenweg - a scale model of the solar system.
The top of the ridge and its east side are covered by the beautiful woods of the
Sihlwald. The Sihl wood was one of the historical sources of fuel and lumber for
the city of Zurich. In 2008 it was declared a National Park. The Sihl river, which
makes an improbable journey from Lake Sihl by Einsiedeln, running parallel to Lake
Zurich until they converge in the city, is nowadays a source of considerable hydropower.
The water of the Sihl and of the many little rivulets that descend into the valley
is hard and quickly coats rocks and wood with a pale pink or yellow coating.