The remains of the Castle can be visited
Iberg Castle

The Iberg castle ruin is on the mountain of the same name in the municipality of Riniken, in the Swiss canton of Aargau. Of this former hilltop castle, only a few remains are visible today.
History+
In the 11th century, Iberg Castle was built on the northeastern edge of the Iberg mountain. The original complex included a main building, a gate, two outbuildings, and a moat designed to protect against attacks from the south. As no written documents about the castle or its inhabitants exist, archaeological excavations are the sole source of information.
Source: Wikipedia · Licence: CC BY-SA 4.0 · Image: http://commons.wikimedia.org/wiki/File:Riniken_Iberg_Burgmauer_8028.jpg
This description draws on the facts documented in the linked Wikipedia article; Wikipedia content is licensed under CC BY-SA 4.0. Wording and editing: Mobile History.
Location: 47.5056, 8.1868