Denmark managed to remain neutral throughout World War One. But as part of preparations to defend this neutrality, a major defence force of 50,000 men was gathered. Most of this force was used to protect Copenhagen. Furthermore, and strictly against international law, the strait of Øresund between Denmark and Sweden was mined on German orders.
This picture shows the digging of trenches in Dyrehaven, a large park on the northern outskirts of Copenhagen. The defence position at Dyrehaven formed part of the major fortifications of Copenhagen. The city was, at the outbreak of war in 1914, heavily reinforced by the building of trenches, artillery batteries and shelters. Reinforcement of the position at Dyrehaven was carried out through private subscriptions. The aim was to close off the area between the fortification, Fortunen, and the strait of Øresund to guard against an attack on the capital from the north.