Hanstholm is a town and port in Thisted municipality in northern Jutland which is the location of Festung Hanstholm, a fortress with its guns trained over the Skagerrak built by the armed forces of the Third Reich immediately after they invaded Denmark on 9 April 1940. It was matched on the Norwegian side of the Skagerrak by Batterie Vara near Kristiansand, now the Kristiansand Cannon Museum. The position of the gun emplacements was altered from March 1942 as part of the construction of the Atlantic Wall. Some 20,000 cubic metres of concrete went into new construction and the guns themselves were moved in October 1942. The four 38 cm guns, whose barrels each weighed 110 tonnes, were intended for the battleship Gneisenau which was severely damaged by bombing. The guns fired only once in anger, on 4 May 1941, when shells were directed on a fishing boat from Skagen which was sheltering from storms, but their implied threat did deter Allied ships from entering the Baltic. The guns were manned by 118 men of a Naval Artillery Battalion, but contingents of other troops provided defence for the battery. The guns were scrapped in 1951-52 and the fortress is now a museum of the Second World War within the Thy National Park, established in 2008, which extends 55 km from north to south through the dunes and heathlands of coastal Jutland. It stands within a wooded landscape characterised by many concrete bunkers which proved too solid to remove. A narrow gauge railway intended to carry shells from underground magazines to the guns conveys visitors across the site. Many artefacts of the Second World War are displayed, including guns intended for defence of the site and military vehicles of many kinds.