This article addresses urban planning adaptation to environmental change and climate change. Historically, cities have always had to respond to environmental influences in order to remain viable in the long term. The article illustrates this through three examples from Vienna. One example is the regulation of the Wien River between 1894 and 1906, which technically reconceived flood protection through the creation of large retention basins west of the city and thereby opened up new development opportunities within the inner city. The district of Lichten-tal, part of Vienna’s 9th municipal district, also underwent transformations due to repeated flooding, particularly through the raising of street levels and all the associated consequences. The 1905 resolution establishing the Vienna Forest and Meadow Belt not only halted further deforestation and development but also aimed to improve air quality and relieve the growing urban area. Today, climate change represents one of the greatest challenges for cities. This also raises the question of how such measures can be integrated into the historic urban context. If we fail to act, there is ultimately the risk that our cities will become uninhabitable due to increasing stress from extreme heat, heavy rainfall, or other extreme weather events.