Big Tower (Store Tårn), Christiansø

A Baltic Stronghold on the Edge of Denmark

The Big Tower, or Store Tårn, anchors the skyline of Christiansø, a tiny granite island northeast of Bornholm that once formed the core of Denmark’s eastern naval fortress. Built in the late 17th century as part of the Ertholmene stronghold, the tower guarded vital shipping lanes in the Baltic. Its massive circular walls, pierced by narrow embrasures, evoke an era when cannons and signal flags ruled these waters, and the entire island operated as a self‑contained military community. From the ramparts around the tower you can still read the island’s defensive layout: low bastions hugging the shoreline, old gun positions facing the sea and the compact cluster of houses that once served officers, soldiers and craftsmen. The Big Tower was both lookout and symbol of royal power, a stone sentinel visible from far out at sea.

From Fortress Tower to Lighthouse Beacon

Around 1800 the Big Tower took on a new role when it was converted into a lighthouse to aid navigation rather than deter enemies. The upper structure was reworked to house a lantern, and for generations its beam has guided ships between Bornholm and the Swedish coast on dark or stormy nights. Inside, you encounter traces of this transition from garrison life to maritime service: steep internal stairs, storage spaces turned into workrooms and exhibits explaining how light technology developed from simple lamps to modern optics. The tower’s stone base retains its fortress character, with heavy masonry and echoing interiors, but higher up the mood shifts. As you climb, narrow windows widen into viewing slits and, near the top, the lighthouse room feels almost airy. The contrast between the rough, centuries‑old stonework and the clean lines of the lighthouse equipment underlines how the building has adapted to changing needs while keeping its historic core intact.

Exhibitions Inside the Granite Walls

Following a major restoration in the 21st century, the Big Tower has been carefully fitted out to host exhibitions and cultural events without overwhelming its historic fabric. Displays typically explore themes such as naval history, life on an isolated island community and the broader story of Ertholmene as a fortress. Archival images, models and artefacts reveal how the bastions, barracks, powder magazines and towers all worked together as a single defensive machine. In some seasons, the tower also serves as a venue for concerts, talks or art installations. The thick walls give performances an intimate acoustic, and contemporary works gain an extra charge from the surroundings: modern art and music unfolding in a space once shaped for war. At quieter times, interpretive panels allow you to explore at your own pace, tracing the lives of soldiers, lighthouse keepers and island families who passed through these rooms.

Views Across the Ertholmene Archipelago

One of the tower’s great rewards is the panorama from the upper levels. Looking out, you see the neighboring island of Frederiksø linked by a narrow bridge, with the smaller Little Tower that now houses a museum about fortress life. Beyond lie low skerries and bird islands, protected areas where seabirds nest on bare rock and seals haul out on ledges. On clear days the horizon stretches towards Sweden and the Polish coast, emphasizing just how exposed and strategic this position has always been. From this height, the pattern of the island town becomes clear: rows of yellow‑washed barracks and houses, red roofs, the small harbor cupped between granite walls and the open Baltic on all sides. The vantage point makes the scale of Christiansø tangible—it is possible to walk around the main island in under an hour—yet the fortifications lend it the gravity of a much larger place.

Experiencing Island Life Around the Tower

Visiting the Big Tower is as much about atmosphere as it is about individual exhibits. Outside, the wind carries the sound of waves slapping against the rocks and the cries of eider ducks and other seabirds. Narrow paths lead from the tower along the curtain walls, past old cannon positions still occasionally used for ceremonial salutes. In summer, grasses and wildflowers push up against the granite, softening the martial outline of the fortress. Because the islands are a protected nature area as well as a heritage site, there is a strong sense of respect for both environment and history. Simple rules help safeguard nesting birds, fragile vegetation and the tranquility of the small permanent community. Time on Christiansø often feels compressed: a few hours circling the ramparts, exploring the towers and watching the changing light over the sea can leave a vivid impression of life lived at Denmark’s farthest maritime frontier.