The ruins of Alt-Thierstein Castle are situated on a wooded ridge in the Laufental valley, near the border with the canton of Basel-Landschaft. This medieval castle was likely built in the 12th century by the Counts of Thierstein and served to control important trade routes. Today, remnants of the walls, the keep, and sections of the curtain wall are still visible. The site offers a beautiful view over the Laufental valley. The ruins are freely accessible and a popular destination for hikers and history enthusiasts.