Flak towers (German: Flaktürme) were 8 complexes of large, above-ground, anti-aircraft gun blockhouse towers constructed in the cities of Berlin (3), Hamburg (2), and Vienna (3) from 1940 onwards. Other cities that used flak towers included Stuttgart and Frankfurt (Main).
They were used by the Luftwaffe to defend against Allied air raids on these cities during World War II. They also served as air-raid shelters for tens of thousands of people and to coordinate air defence.
The Holsten Gate ("Holstein Tor", later "Holstentor") is a city gate marking off the western boundary of the old center of the Hanseatic city of Lübeck. This Brick Gothic construction is one of the relics of Lübeck’s medieval city fortifications and the only remaining city gate, except for the Citadel Gate ("Burgtor"). Because its two round towers and arched entrance are so well known it is regarded today as a symbol of this German city, and together with the old city centre (Altstadt) of Lübeck it has been a UNESCO World Heritage Site since 1987.
