Subdistrict [Bezirkteil] of Vienna, part of the 13th district (Hietzing -- the third largest district, which is divided into six subdistricts), lying to the West of the city. Containing a nature reserve (the Lainzer Tiergarten), it served in the 19th and early 20th centuries as a summer recreational area for members of the Viennese nobility and wealthy middle class.