for the foot." One million kronor was allocated in 1915 to fix that problem, and many minor fortifications were built during the First World War. Blockhouses were also built by the railway bridge at Trångforsen and the road bridge Hedenbron (built from 1911 to 1912), located just southeast of the Trångforsen bridge. The later was built to accommodate easier access to Rödberget Fort and the military training area on the southwestern shore of Lule River and was at the time of completion the longest single span road bridge in Sweden. Both internal and external communication systems as well as means of reconnaissance were needed, both directed by the commandant located in the headquarters building. The building—finished in 1910—had three floors, the upper two functioned as home and workplace for the commandant and the chief of staff, while the ground floor had extra thick walls and functioned as the command post for the fortress. A large field telephone network was built, connecting all forts with the headquarters. Liaison with higher commands was at first maintained by regular post, telegraph and telephone. The fortress' radio station was finished by 1914, originally for the Swedish Navy, and was located south of Degerberget on a bog now known as the "Radio Mire" (). The first Swedish radio broadcasts were sent from this building. The fortress also had homing pigeons for sending messages. At the end of the Second World War, around 280 such pigeons were stationed in Boden. The pigeons were part of the balloon department whose main task was to operate the balloon of the garrison. For this, the Balloon Hangar with inner measurements of was built near the radio station. More than fifty men were attached to the department, of whom two could follow the balloon up to its maximum height of , limited by the length of the wire connecting it to the ground. The hydrogen-filled balloon itself was of German make and measured in length, had a diameter of around and a total volume of . In operation Two World Wars Most parts of the fortress were finished during the First World War, and many minor works were started and completed during the course of the war. Even though Sweden remained neutral during the First and Second World War, the start and outcome of both had large impact on the fortress. Finland's independence during the First World War created a