Tunaborgen is a ruined former bishop castle. In 1291 Archbishop Nils Alleson mentioned a fortification on the site. The fort was also a strategic point in the Gustav Vasa's war against the Danes.
The ruins were rediscovered around 1920. The castle consisted of a square tower, a citadel, built together with an almost square walls and it was surrounded by a circular moat. Today the ground floor remains.References:
Les Invalides is a complex of buildings containing museums and monuments, all relating to the military history of France, as well as a hospital and a retirement home for war veterans, the building"s original purpose. The buildings house the Musée de l"Armée, the military museum of the Army of France, the Musée des Plans-Reliefs, and the Musée d"Histoire Contemporaine, as well as the burial site for some of France"s war heroes, notably Napoleon Bonaparte.
Louis XIV initiated the project in 1670, as a home and hospital for aged and unwell soldiers: the name is a shortened form of hôpital des invalides. The architect of Les Invalides was Libéral Bruant. The enlarged project was completed in 1676, the river front measured 196 metres and the complex had fifteen courtyards. Jules Hardouin Mansart assisted the aged Bruant, and the chapel was finished in 1679 to Bruant"s designs after the elder architect"s death.
Shortly after the veterans" chapel was completed, Louis XIV commissioned Mansart to construct a separate private royal chapel referred to as the Église du Dôme from its most striking feature. Inspired by St. Peter"s Basilica in Rome, the original for all Baroque domes, it is one of the triumphs of French Baroque architecture. The domed chapel is centrally placed to dominate the court of honour. It was finished in 1708.
Because of its location and significance, the Invalides served as the scene for several key events in French history. On 14 July 1789 it was stormed by Parisian rioters who seized the cannons and muskets stored in its cellars to use against the Bastille later the same day. Napoleon was entombed under the dome of the Invalides with great ceremony in 1840. In December 1894 the degradation of Captain Alfred Dreyfus was held before the main building, while his subsequent rehabilitation ceremony took place in a courtyard of the complex in 1906.
The building retained its primary function of a retirement home and hospital for military veterans until the early twentieth century. In 1872 the musée d"artillerie (Artillery Museum) was located within the building to be joined by the Historical Museum of the Armies in 1896. The two institutions were merged to form the present musée de l"armée in 1905. At the same time the veterans in residence were dispersed to smaller centres outside Paris. The reason was that the adoption of a mainly conscript army, after 1872, meant a substantial reduction in the numbers of veterans having the twenty or more years of military service formerly required to enter the Hôpital des Invalides. The building accordingly became too large for its original purpose. The modern complex does however still include the facilities detailed below for about a hundred elderly or incapacitated former soldiers.