The former Imperial Palace (Kaiserpfalz) in Kaiserslautern was built in around 1152 by Emperor Frederick I Barbarossa. The only remaining parts of the Imperial Palace are a few carved blocks of red sandstone and remnants of the stone outer wall of the double chapel added by Frederick II.
Following the excavation of the rest of the Imperial Palace and the evaluation of the findings, the city mounted the historic foundations. The Domus (imperial building) originally measured 25 by 19 meters and was 19 meters high. In order to get a real sense of the size of the building, a 3D steel and tamped concrete construction that imitates the size and shape of the Imperial Palace was built.
You can see the remains of the castle wall, which have now been fully uncovered, just next to what was the Imperial Palace. The Stapf fortress was also rebuilt in this location. The fortress was erected at the beginning of the Thirty Years’ War, in around 1619/1620, by fortress builder Adam Stapf on the orders of the widow of Frederick IV, Elector Palatine of the Rhine. Stapf built primary defensive walls with trenches, bastions and curtain walls which protected the medieval castle and city walls.
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.