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:Inverness Castle sits on a cliff overlooking the River Ness. The red sandstone structure evident today was built in 1836 by architect William Burn. It is built on the site of an 11th-century (c. 1057) defensive structure. Today, it houses Inverness Sheriff Court.
The castle is said to have been built by Máel Coluim III of Scotland, after he had razed to the ground the castle in which Macbeth of Scotland according to much later tradition, murdered Máel Coluim"s father Donnchad I of Scotland, and which stood on a hill around 1 km to the north-east.
The first Inverness Castle was partially destroyed by King Robert I of Scotland and a replacement castle was sacked in the 15th century by the Clan Donald during the Siege of Inverness (1429). The castle was occupied during the Raid on Ross in 1491.
In 1548 another castle with tower was completed by George Gordon, 4th Earl of Huntly (1514–1562). He was constable of the castle until 1562.