Heligoland | The Gibraltar of the North Sea

Long military history

Heligoland, spelled Helgoland in German, has a long military history because of its strategic location. Occupied originally by Frisian herdsmen and fishermen, the island came under the control of the dukes of Schleswig-Holstein in 1402 and became a Danish possession in 1714. Seized by the British navy in 1807, it was formally ceded in 1814 to Britain, which in 1890 transferred it to Germany in exchange for Zanzibar and other African territories.

Gibraltar of the North Sea

The Germans developed the island into the “Gibraltar of the North Sea” with a great naval base, extensive harbour and dockyard installations, underground fortifications, and coastal batteries. In constant use by German naval forces in World War I, the military and naval works were demolished in 1920–22 in accordance with the Treaty of Versailles, and the island became a popular tourist resort.

The German island the British tried to destroy

Under the Nazi regime, however, it was again made a naval stronghold and sustained severe Allied bombing toward the end of World War II. Before its destruction, the town of Heligoland extended from the Unterland to the Oberland. With the defeat of Germany, the population was evacuated, and the British occupation authorities changed the physical character of much of the island when they destroyed the remaining fortifications, underground bunkers and submarine base by deep blasting, and at the same time record the explosion with seismic sensors for science.

A blast from the past

On 18 April 1947, the Royal Navy detonated 6,700 tons of explosives creating a black mushroom cloud that curled 6,000 feet into the sky. People on the mainland 60 km away were warned to open their windows to avoid implosion, and the blast was registered as far away as Sicily. The Guinness Book of World Records lists the Heligoland explosion as the world’s largest single non-nuclear explosion in history.

The island was used as a bombing range by the Royal Air Force until it was returned to West Germany on March 1, 1952. The town, the harbour, and the bathing resort on Düne have been rebuilt. 

Not to be missed

  • Join a bunker tour
  • Spot grey seals mate, give birth and raise their young on Düne beach
  • Relax in the island’s spa. In 1826, Heligoland became a seaside spa and soon it turned into a popular tourist resort for the European upper class.
  • Take the elevator to Oberland and walk around the red sandstone cliffs

More info

Heligoland: the German Island the British Tried to Destroy

Heligoland: Germany’s hidden gem in the North Sea

Heligoland on Dark Tourism