A multitude of port cities dot Europe’s coastline, each with its own history and relationship to sea transportation and development. In the era of climate change, these cities can offer paradigms and guidance for sustainable development. Taking a comprehensive, map-based approach, Port City Atlas offers visualizations of 100 port city territories located on four seas and connected through shared waters—from Amsterdam, Antwerp, Barcelona, Bilbao, Bordeaux, Bremen, Calais, Cork, Dover, Dublin, Felixstowe, Fredericia, Ghent, Hamburg, Helsinki, Kiel, Københavns and La Rochelle to Limerick, Liverpool, London, Lübeck, Malmø, Palermo, Ravenna, Riga, Rønne, Rotterdam, Sköldvik, Stockholm, Tallinn, Venice, Zeebrugge and countless others. Conceived as a reference work, Port City Atlas provides a foundation for comparative analysis beyond the case-study approach, offering a uniquely sea-oriented take on the understanding and urban design of Europe.