"Wiener Null"

In 19th century Vienna was bounded by topographic elements of the hilly landscape and marsh land. Therefore, it could not easily spread and the regrading of the townscape was undertaken. Thus far, these aspects of historic urban planning have been relatively unexamined; this paper offers some essential findings.Grading adjustments occurred in the course of the two major city extensions or was triggered by infrastructural installation work. Further levelling was engaged—and organised by building codes—in order to improve traffic flow and for flood mitigation. The latter became the most effective intervention as it fundamentally restructured all low-lying districts.