 The site of Baldern Castle lies within the municipal boundaries, on the Albis ridge.Only earthworks remain, but early chronicles suggest that the castle was built by Ludwig the German, the first king of East Francia, in 853AD, and the castle is known to have been owned by the Counts of Lenzburg in the 12th century.There have been no significant archeological investigations of the site, and the date and reason it was abandoned is unknown.