Ehn apprenticed under
Otto Wagner, began working for the Vienna City Administration in 1908, and as City Architect of Vienna was responsible for many
Gemeindebau (public housing projects) of the 1920s and 1930s. It is estimated that Ehn designed a total of 2,716 flats during his career. Initially his designs were informed by the English
Garden City movement as shown by his early commission at Hermewiese (1923). His most notable single design remains the colossal
Karl Marx-Hof (1926-1930), the largest and best example of innovative public housing built during the Socialist
Red Vienna movement. According to
Joseph Rykwert, Ehn continued to serve the city through the
Anschluss in 1938 and afterwards until 1950. == Work ==