Ruine Alt-Lägern, Castle ruin in Boppelsen, Switzerland.

Ruine Alt-Lägern is a medieval castle complex perched on a hillside near Zurich with stone walls that are now partially moss-covered. The rectangular ground plan remains clearly visible, and the site sits at about 866 meters elevation among fields and forests.

Lütold V, baron of Regensberg, founded the town of Regensberg between 1244 and 1246 and had Lägern castle built as the seat of his ministerials, the knights of Lägern. The castle was destroyed before 1300, possibly in the Regensberg feud of 1267, after which the lords of Lägern fell into poverty and died out.

The ruins display medieval building methods typical of the region and tell of power structures from that era. Visitors can still see the ground plan and understand how such places controlled the land and people around them.

Several hiking trails lead to the site from different directions, giving visitors various access options. At the base of the structure there is a barbecue area where you can rest and enjoy the views.

Excavations from 1902 to 1904 uncovered living spaces that show people once lived and worked here. Surprisingly, archaeologists never found the foundation of a tower, even though castles typically had one.