Among the numerous iron mines of the 18th and 19th centuries around Warstein was also the open pit mine "Martinus" in Stillenberg, here located in the park area of the LWL Clinic, above the Elisabeth Church. Around 1900, the Martinus mine was shut down. Since the construction of the psychiatric clinic, the former open-pit mine site has served as an open-air stage and fairground - an early "cultural after-use" of a former mining site.

The Treise Chapel, which now stands on the grounds of the LWL Clinic, dates back to a chapel that originally stood in the vicinity of the Warstein ironworks. The chapel is now a memorial to the 1576 women and men who fell victim to "euthanasia," killing for "racial hygiene reasons" during the Nazi era. Visitors can pick up the key at the information center on the ground floor in Building 12.