Sct. Hans Hospitals Museum tells the history of Roskilde's psychiatric hospital, founded in 1860 and once considered one of the most modern institutions of its kind. The displays focus on the hospital, its patients, and changing ideas about mental health care.
It is a small, specialist museum rather than a headline attraction, but it adds a different layer to Roskilde beyond the cathedral, fjord, and Viking ships. Check opening hours before visiting, as access can be limited.