The Round Tower (Rundetaarn), Copenhagen

A royal tower above the old Latin Quarter

Completed in 1642 for King Christian IV, the Round Tower rises quietly from the narrow shopping street of Købmagergade, just where Copenhagen’s old Latin Quarter begins. Conceived as part of the Trinitatis complex, it combined observatory, university library and church in one ambitious design, a physical expression of the era’s fascination with science, faith and scholarship. Today it still anchors the skyline with its robust brick cylinder and copper dome, a familiar landmark among the city’s jumble of spires. From street level the tower looks almost austere, but step closer and details emerge: brickwork laid in warm, earthy tones, arched windows punctuating the façade, and monograms and inscriptions hinting at royal origins. The structure has survived fires, wars and urban renewal around it, remaining largely intact while the city transformed below.

The spiral ramp and hollow heart of the tower

Inside, the tower reveals its most distinctive feature: a broad, cobbled spiral ramp that climbs about 200 metres in a gentle corkscrew. Instead of stairs, this sloping corridor was designed wide enough for horses and even small carriages, so instruments and books could be hauled to the observatory and library above. The whitewashed walls curve smoothly as you ascend, with small alcoves and windows opening to shafts of changing daylight. Near the upper levels, a glass floor spans the hollow core of the tower, allowing you to peer down into the shaft far below. It offers a striking sense of the building’s engineering and is a favourite pause point for those steady enough on their feet. Higher still, the ramp gives way to a wooden staircase and a final tight stone spiral, underscoring how the ascent becomes progressively steeper and more intimate as you approach the summit.

The Library Hall: books, art and culture in the sky

Roughly halfway up sits the Library Hall, a long, bright space that once housed the entire university library. For two centuries this was the intellectual attic of Copenhagen, stacked with thousands of volumes above the city streets. Today the shelves are gone, replaced by temporary exhibitions that range from contemporary art and photography to science and history, as well as concerts, talks and family activities. High windows funnel soft light across wooden floors, giving the hall an almost ecclesiastical calm despite its changing programme. A small shop and café counter add a relaxed pause point in the middle of the climb, with postcards, books and design objects echoing the tower’s themes of astronomy and architecture.

Skyline views and the historic observatory

At the top, an open circular platform wraps around the observatory dome, enclosed by a wrought-iron balustrade. From here the city unfurls in every direction: the green copper spires of nearby churches, the formal gardens and turrets of Rosenborg Castle, the distant sweep of the harbour and, on clear days, the hazy line of Sweden across the Øresund. The view is low and intimate rather than vertiginous, more about reading the city’s layers than sheer height. Within the dome sits one of Europe’s oldest functioning observatories, where astronomers once charted the night sky for the Danish crown and university. On selected evenings outside restoration works, the telescope is used for public stargazing, continuing a tradition of observing planets and star clusters from the very heart of the city.

Experiencing the tower today

Visiting the Round Tower is as much about atmosphere as it is about individual sights. The slow, steady incline encourages an unhurried pace, with the curve of the ramp hiding what comes next until you gently round each bend. Sound carries in soft echoes: children’s footsteps, snippets of conversation in different languages, the muffled rumble of the city fading as you climb. Despite its central location, the interior feels self-contained and almost monastic, a space where centuries of scholarly work, observation and quiet contemplation have left a subtle imprint. Whether you come for a quick city view, an exhibition in the Library Hall or an evening under the observatory dome, the tower offers a compact journey through Copenhagen’s scientific and architectural history in a single graceful ascent.