Fårösund is a decommissioned fortress, built from 1885 to 1886. Sweden's capacity to protect its neutrality was questioned after the Crimean War 1854–56. England and France persuaded Sweden to fortify the inlet at Fårö with artillery batteries and naval mines. The fortress consisted of three fixed batteries. At the turn of the century, the batteries were reconstructed. The batteries I and II were given modern quick-firing 57 mm guns, four per battery. In 1919 the fortress was closed down and all equipment removed. After the fortress was closed down and was taken over by the Swedish Prison and Probation Service in 1919, a penitential center was establishment. The fortress had been proposed as a detention center for social dangerous offenders, if and when legislation for such came about.
Today the fortress is a hotel and restaurant.
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.