a straight angle. One of the main tunnels served as crew quarters while the other was in direct connection with the above ground artillery pits. The fortress' artillery consisted of two and four positional artillery pieces in half-turrets placed in pits dynamited from the rock and lined with concrete, as well as four Krupp M/1887 field guns. The pieces, designed before the advent of recoil systems, were described by the Germans after the 1940 surrender as Napoleonic. The positional artillery is placed in an almost straight line facing east, with a distance between each gun and between each piece. To enable the fortress to withstand attack without support from outside a wide barbed wire obstacle was constructed encircling the entire fortress. Early period During the period 1910 to 1926 the fort was used as a major military base for the Trøndelag border areas with Sweden. In 1926, Ingstadkleiva Fort was put in reserve as part of the post-World War I defence budget cuts. Deactivated period From 1934–1939, the deactivated fort was used by the Norwegian Red Cross's youth branch as a summer holiday camp for children. In late 1939, Finnish soldiers of the independent Lapland Group who had crossed the Norwegian border into Finnmark escaping the fighting in the Petsamo district in northern Finland were interned at Ingstadkleiva Fort. All the Finns were repatriated during the early days of 1940. During the Finnish internees' stay a sauna was constructed at the fort's camp. Norwegian Campaign In 1940, from 15 April to 5 May, Hegra was attacked by the German invaders. During the first week the attacks consisted of two infantry assaults; however in the last two weeks attacks mostly featured heavy artillery fire and Luftwaffe bombing, as well as aggressive patrolling. During the siege large portions of the fort were covered in snow, and as all plans of the fort were stored in German-occupied Trondheim several sections of the fortifications were not discovered by the defenders before the 5 May surrender. Present-day fortress After the end of the Second World War, Hegra Fortress was returned to Norwegian control and is today used as a museum with exhibitions detailing the fort's history with an emphasis on the 1940 siege. There is also a café and a souvenir shop. The museum is often used for conferences and for seminars on issues of war and peace. Hegra Fortress is still owned by the