Coppenbrügge Castle is a well-preserved moated castle ruin in the town of Coppenbrügge, Lower Saxony.
After losing their ancestral seat, the Counts of Spiegelberg acquired land in Coppenbrügge in 1281 and built a moated castle to control a major trade route. First documented in 1303, parts of the original structure like the gate and moat still exist. Damaged in the 1434 Spiegelberg Feud, the castle was rebuilt in the Renaissance style after the counts inherited Pyrmont in 1494 and moved their seat there.
The castle passed through several noble families, including the Houses of Lippe, Gleichen-Thonna, and Nassau. By the late 1600s, it was in disrepair. In 1697, Tsar Peter the Great met with Electress Sophie of Hanover here, an event remembered as the 'Ladies' Peace of Coppenbrügge.'
A baroque palace was added before 1745 but later demolished after the castle was sold to the Kingdom of Hanover in 1822. Most buildings were torn down by 1870, except for a timber-framed chancery house, now a museum. The castle briefly served as a quarry in 1945.
The castle is surrounded by a water moat and earthen wall. The southern courtyard houses a former court building. Medieval foundations are visible in the north, east, and west. The gatehouse is flanked by two round towers, one used as a bastion.
A highlight is the Peterlinde, a centuries-old linden tree on the castle wall, linked to Tsar Peter's 1697 visit. Estimated to be 500–700 years old, it once formed a walkable tree pavilion connected to the castle.
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.