Vienenburg Castle is a ruined hilltop castle near the town of Vienenburg in Lower Saxony, located about 165 meters above sea level.
Its origins are unclear, though it may have been built around 1300 using stones from the destroyed Harliburg. The likely founder was Count Burchard VII of Wernigerode, supporting the Bishop of Hildesheim. First mentioned in 1306, the castle changed hands many times—mortgaged to Goslar in 1341, transferred to the bishops of Hildesheim in 1367, and taken by the Duchy of Brunswick-Wolfenbüttel in 1523 after the Hildesheim Diocesan Feud. Wallenstein used it as a base during the Thirty Years’ War. From 1643 to 1802, it returned to Hildesheim, then passed to Prussia with secularization.
Parts of the castle were dismantled for building materials. The 24-meter-high round tower (bergfried) was renovated in 1853 and again in 2010, and now serves as a lookout tower.
The irregular castle site (max. 85 × 125 m) stands on a steep ridge above the Oker valley. It is accessed from the east via a ditch. Some estate buildings, partially timber-framed, still lean against the old 1-meter-thick curtain wall. The entrance gatehouse features a 1725 Hildesheim coat of arms. Foundations of the former great hall and a stair tower also remain.
Duino Castle was built by the Wallsee family in 1389 on the cliffs overlooking the Gulf of Trieste. It replaced an older castle from the 11th century. Over time, the Wallsee family disappeared and the castle, after having been used as a prison, became the residence of the Luogar and Hofer.
At the end of the 19th century it became the property of Prince Alexander von Thurn und Taxis from the Czech branch of the House of Thurn and Taxis. It remains with the family to this day with his great-grandson Prince Carlo Alessandro della Torre e Tasso, Duke of Castel Duino the current owner. The castle has been opened to the public as a museum and park.