Munkholmen is an islet which has served as a place of execution, a monastery, a fortress, prison, and a World War II anti-aircraft gun station.
In the years prior to the founding of the city of Trondheim in 997 by Viking King Olav Tryggvason, Munkholmen was used as an execution site by the Jarls of Lade. The arrival of Olav Tryggvason to Norway in 995 coincided with a revolt against Haakon Sigurdsson, who was killed by Tormod Kark. The severed heads of both Haakon and Kark were placed on stakes on Munkholmen facing out into the fjord to serve as a warning to visitors. Legend has it that before entering Trondheim, visitors were made to spit on these heads as a tribute to King Olav I of Norway. The tradition of displaying the severed heads of criminals and political opponents was continued for some time, but the heads were now placed so that they faced the city of Trondheim to deter its citizens from committing crimes.
In the early 12th century, and possibly even earlier, Benedictine monks lived on the island in Nidarholm Abbey. Local stories claim the monastery was quite lively and that on several occasions requests came from the mainland to keep the noise down. By the time Lutheran Protestantism came to Trondheim, the monastery had fallen into decay.
Construction of a fort on the island began in 1658. When it was completed in 1661, the fort was also used as a state prison for society's rejects. Count Peder Griffenfeld, Munkholmen's most famous prisoner, was transferred from the fortress of Copenhagen in 1671. Griffenfeld was kept at Munkholmen for 18 years, after which he was released, having contracted a terminal illness. The fort remained in operation until 1893.
Nazi Germany invaded and occupied Norway in 1940. After capturing Trondheim early on in the Norwegian Campaign, the Germans quickly established a submarine base, exploiting the natural protection provided by the fjord. At this time, Munkholmen was fitted with anti-aircraft weaponry. A large portion of the fort was retrofitted to hold ammunition, and the flooring planks were nailed in with wooden nails to prevent explosions caused by soldiers' boots striking metal nails. The German occupying forces remained in Norway until the end of the war in Europe in May 1945. Remnants of the installation still exist in the upper levels of the fort.
Today, Munkholmen is a popular summertime tourist attraction and hangout for residents of Trondheim. From May to September, boats depart from Ravnkloa on a regular basis. Once on the island, visitors can take a guided tour (in English and Norwegian) or roam freely. There's also a small cafe/restaurant available.References:
Ängsö Castle was first named as "Engsev" in a royal charter by king Canute I of Sweden (r. 1167-1196), in which he stated that he had inherited the property after his father Eric IX of Sweden. Until 1272, it was owned by the Riseberga Abbey, and then taken over by Gregers Birgersson.
From 1475 until 1710, it was owned by the Sparre family. The current castle was built as a fortress by riksråd Bengt Fadersson Sparre in the 1480s. In 1522, Ängsö Castle was taken after a siege by king Gustav Vasa, since its owner, Fadersson's son Knut Bengtsson, sided with Christian II of Denmark. However, in 1538 it was given by the king to Bengtsson's daughter Hillevi Knutsdotter, who was married to Arvid Trolle.
In 1710, the castle was taken over by Carl Piper and Christina Piper. Ängsö Castle was owned by the Piper family from 1710 until 1971, and is now owned by the Westmanna foundation. The castle building itself was made into a museum in 1959 and was made a listed building in 1965. It is currently opened to visitors during the summers.
The castle is a cubical building in four stores made by stone and bricks. The lower parts is preserved from the middle ages. It was redecorated and expanded in the 1630s. The 4th storey as well as the roof is from the expansion of Carl Hårleman from 1740-41. It gained its current appearance in the 1740s.