Elfsborg Fortress, Fort in Älvsborg, Gothenburg, Sweden

Oscar II's Fort, the main facility of Elfsborg Fortress, is blasted into the bedrock of Västerberget on the mainland in Gothenburg's Älvsborg district. It holds several hundred metres of passages with offices, lodgings, messes and stores for 300 men, and is surrounded by a moat with two counterscarp galleries.

Construction of Oscar II's Fort on Västerberget began on 24 August 1899, when King Oscar II fired the first blasting shot. The name Älvsborg Fortress was given to the new coastal fortress on 27 April 1904, and the fort was in service from 1907 to 1955. In 1942 it became part of Gothenburg Coastal Artillery Defence and headquarters of KA 4; the spaces were used for storage until the 1970s.

The name Älvsborgs fästning was formally given to the new river-mouth fortress on 27 April 1904, while its main work honours King Oscar II, who fired the first blasting shot on 24 August 1899. The Götiska batteriet outside the fort was donated by the Geatish Society. On 4 November 1926 a farewell salute greeted King Albert I of Belgium, the last salute fired from the fortress.

The fort is cut into Västerberget in the Älvsborg district of Gothenburg, not on an island; reach it on foot or by local transport. The underground passages are cool and uneven, so wear sturdy shoes. The State Property Agency manages the site, which is opened to the public at regular times.

When the 24 cm guns fired, residents of Långedrag had to open their windows so the blast would not shatter the glass. The guns sat in open wells on disappearing carriages, rising to fire and sinking below the edge to be reloaded.