The Church of St Leopold was built by Otto Wagner between 1904 and 1907 as part of a psychiatric complex, its large green copper dome standing proudly atop the hillside where the hospital is situated. Otto Wagner used the same kind of marble cladding for the church as he did for the Post Office Savings Bank he designed, and also took the same care with the furnishings designed for the patients. The richly decorated interior has stained-glass windows by Koloman Moser and mosaics.