Visitation stones on the memorial for the Austrian Jews on Viennas Judenplatz. The practice is a way participating in the mitzvah of burial. The stone is placed by the left hand. Marking a grave with stones was customary in Biblical times before the adoption of gravestones. The memorial is dedicated to the memory of the 65000 Austrian Jews murdered by the nazi regime between 1938 and 1945. The exterior walls are formed by a pattern of stylized books. The memorial (Mahnmal) is the work of British artist Rachel Whiteread.