Flak towers (Flaktürme) were eight complexes of large, above-ground, anti-aircraft gun blockhouse towers constructed by Nazi Germany in the cities of Berlin, Hamburg, and Vienna from 1940 onwards. The towers were used by the Luftwaffe to defend against Allied air raids against these cities during World War II. They also served as air-raid shelters for tens of thousands of local civilians.
In Vienna military authorities chose the Augarten as one of several places to erect massive buildings for anti-aircraft defence to protect the inner city from Allied bombing. During summer 1944 the construction of a 55 metre high tower with platforms for anti-aircraft guns and nearby also a 51 metre high control tower was begun but not finished. Their remains are still visible in the middle of the park. Moreover during the war hundreds of cubic metres of rubbish were dumped on the site whilst armoured vehicles criss-crossed the garden and - as it is supposed - common graves were dug for hundreds of war victims.
References:The Château du Lude is one of the many great châteaux of the Loire Valley in France. Le Lude is the most northerly château of the Loire Valley and one of the last important historic castles in France, still inhabited by the same family for the last 260 years. The château is testimony to four centuries of French architecture, as a stronghold transformed into an elegant house during the Renaissance and the 18th century. The monument is located in the valley of Le Loir. Its gardens have evolved throughout the centuries.