Stormont Castle is a mansion in east Belfast which is used as the main meeting place of the Northern Ireland Executive. It was never a castle as such: the original building was reworked in the nineteenth century in the Scottish baronial style with features such as bartizans used for decorative purposes.
Between 1921 and 1972, it served as the official residence of the Prime Minister of Northern Ireland. However, a number of prime ministers chose to live at Stormont House, the official residence of the Speaker of the House of Commons of Northern Ireland, which was empty as a number of speakers had chosen to live in their own homes. It also served as the location of the Cabinet Room of the Government of Northern Ireland from 1921 to 1972.
Before devolution it served as the Belfast headquarters of the Secretary of State for Northern Ireland, Northern Ireland Office Ministers and supporting officials. During the Troubles, it was also used by MI5 officers.
The castle is open to the public each year on the European Heritage Open Day weekend.
References: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.