Background

The Round Tower (Rundetårn), Copenhagen

Seventeenth‑century science, a storybook spiral ramp and a 360‑degree skyline view come together in Copenhagen’s Round Tower, Europe’s oldest working observatory.

4.5

Rising above the cobbled streets of central Copenhagen, the Round Tower is a 17th‑century architectural one‑off: a cylindrical brick tower climbed not by stairs but by a broad spiral ramp that curls 7½ times to the top. Built in 1642 by King Christian IV as part of the Trinitatis Complex, it combined an astronomical observatory, university library and church under one roof. Today it doubles as Europe’s oldest functioning observatory and a cultural venue, with exhibitions in the old Library Hall and a breezy 360‑degree city panorama from the viewing platform.

A brief summary to The Round Tower

  • Købmagergade 52A, Copenhagen, Indre By, 1150, DK
  • +4533730373
  • Visit website
  • Duration: 1 to 2 hours
  • Budget
  • Environment icon Mixed
  • Mobile reception: 5 out of 5
  • Monday 10 am-6 pm
  • Tuesday 10 am-9 pm
  • Wednesday 10 am-9 pm
  • Thursday 10 am-6 pm
  • Friday 10 am-6 pm
  • Saturday 10 am-6 pm
  • Sunday 10 am-6 pm

Local tips

  • Arrive soon after opening or later in the afternoon on weekdays to enjoy the spiral ramp and viewing platform with fewer crowds and gentler light over the rooftops.
  • Wear comfortable shoes: the 200‑plus metre ramp is a steady incline, and the final stretch to the top involves a short, narrow staircase.
  • Check current exhibitions and observatory opening evenings in advance so you can combine the panorama with either an art show or a stargazing session.
  • On windy or chilly days, bring an extra layer; the outdoor platform is exposed, even though the ascent inside the tower stays pleasantly sheltered.
  • Look for the golden rebus on the facade before you enter and the hollow core window partway up the ramp to appreciate two of the tower’s most intriguing details.
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Getting There

  • Metro and short walk from central Copenhagen

    From many central districts, the quickest route is to take the M1 or M2 metro to Nørreport Station, one of the city’s main hubs; trains run every few minutes and a single zone ticket typically costs around 20–30 DKK. From Nørreport, allow 5–10 minutes on foot along flat, cobbled pedestrian streets to reach Købmagergade and the Round Tower. The walk is step‑free but can be crowded, so build in a little extra time if travelling with a stroller or wheelchair.

  • City bus through the old town

    Several inner‑city bus lines stop near Nørreport and at points along Købmagergade or adjacent streets, with journeys across the central area usually taking 10–20 minutes depending on traffic. A standard bus ticket within the city centre costs roughly 20–30 DKK and is valid across buses, metro and S‑trains within the same zones. Buses can be a good option in bad weather, but note that they may be slower during rush hour and drop you a short walk away on paved streets.

  • Bicycle via Copenhagen’s cycle network

    For a local‑style arrival, rent a city bike or use a bike‑share service and follow the extensive cycle lanes towards Indre By; most central neighbourhoods are within a 10–20 minute ride. Expect daily rental from around 100–150 DKK, or a smaller per‑minute fee with app‑based bikes. There is limited bike parking on side streets near Købmagergade and cycles are not allowed inside the tower, so bring a good lock and be prepared to walk the last stretch through pedestrian areas.

  • Walking from nearby central attractions

    If you are already exploring the historic centre, reaching the Round Tower on foot is straightforward and rewarding. From landmarks such as City Hall Square, Nyhavn or Rosenborg Castle, plan on 10–20 minutes’ walk on mostly level, often cobbled streets. The area is compact but busy, and some surfaces can be uneven, so comfortable footwear is advisable and travellers with reduced mobility may prefer combining walking with metro or bus for part of the journey.

The Round Tower location weather suitability

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Discover more about The Round Tower

A spiral landmark in the heart of old Copenhagen

The Round Tower rises above the pedestrian bustle of Købmagergade, its cylindrical brick walls and gilded rebus instantly recognisable in Copenhagen’s skyline. Completed in 1642 as part of King Christian IV’s ambitious Trinitatis Complex, it was conceived as a practical monument to learning, bringing together an observatory, a university library and a church in a single ensemble. From street level, the tower’s restrained Dutch Baroque detailing and warm brickwork feel solid and almost understated, but its true surprise lies inside. Step through the arched entrance and the city noise falls away into the cool interior of the famous spiral ramp. This gently sloping, white‑washed corridor coils around a hollow core for more than 200 metres, wide enough for horses and carts that once hauled astronomical equipment to the top. The space is simple yet dramatic: light filters in through small windows, footsteps echo against vaulted ceilings, and alcoves open unexpectedly onto views or exhibits, turning the ascent into a slow, cinematic reveal.

From royal observatory to living “star castle”

The tower was built at a time when Denmark wanted to stand at the forefront of the Scientific Revolution. Christian IV commissioned it so astronomers from the University of Copenhagen could observe the heavens above the city smoke. For centuries the observatory at the summit was the nerve centre of Danish astronomy, home to figures such as Christian Longomontanus and later observers who mapped the sky, took meteorological readings and refined navigation techniques vital to a seafaring nation. Although modern research has since moved elsewhere, the Round Tower still functions as an observatory and is often described as Europe’s oldest working example of its kind. The current dome and telescope date from the early 20th century, and on selected evenings the observatory opens for public stargazing. Standing by the brass and glass of the refractor while the dome’s shutters slide open, you feel the building’s original purpose snap into focus: this was a practical scientific tool long before it became a tourist icon.

Library Hall, church and stories in the walls

Halfway up the ramp, a wooden doorway leads into the Library Hall, a lofty, timber‑roofed space that once stored the University of Copenhagen’s book collection above Trinitatis Church. The hall’s plank floors, white arches and exposed beams retain a scholarly atmosphere, even though the shelves now host art exhibitions, installations, concerts and lectures. It was here that a young Hans Christian Andersen came to read and write; the Round Tower later found its way into his fairy‑tale imagery. Beneath all this, Trinitatis Church forms the complex’s spiritual anchor. While access routes vary, the awareness that you are circling a church roof and former library as you climb adds a vertical layering of meanings: devotion at ground level, study in the middle, and observation of the universe at the top. Even the exterior bears a message. The golden rebus wrapped around the facade blends Latin, Hebrew and symbols, usually translated as a plea that God guide learning and justice into the heart of King Christian IV.

Panoramic city views and curious anecdotes

At the top, the ramp finally gives way to a narrow stair and then the open viewing platform, encircled by a wrought‑iron balustrade. From here you can trace the jagged line of Copenhagen’s spires, the copper roofs of Christiansborg and the domes and towers that punctuate the old centre. On clear days, your gaze stretches towards the harbour, modern waterfront districts and, in the distance, the Øresund Bridge linking Denmark and Sweden. The height is modest by modern standards, but the central location and the absence of high‑rises nearby make the panorama unusually intimate. The tower is also rich in anecdotes. In 1716, Peter the Great famously rode a horse up the ramp, and centuries later an early motorcar made the same ascent. During more turbulent times, the structure served as a lookout and even a shelter. Today the drama is gentler: children race ahead up the incline, musicians sometimes perform in the Library Hall, and seasonal exhibitions transform the interior without disturbing its historical bones.

Experiencing the tower today

Visiting the Round Tower is as much about the journey as the destination. The slow, spiralling climb gives you time to notice details: worn cobbles underfoot, small niches in the masonry, changing light through the windows, and occasional glimpses into the hollow core. In places the ramp opens into small exhibitions about the tower’s history, its scientific instruments or the Trinitatis Complex as a whole, adding context without overwhelming the experience. The tower is compact enough for a short visit yet layered enough to reward lingering. You can spend a quiet moment in the Library Hall, circle the outdoor platform several times as the weather shifts, or simply lean against the railing to listen to the city below. Whether you come for astronomy, architecture or a sweeping view over tiled roofs and church spires, the Round Tower offers a dense slice of Copenhagen’s past and present in one beautifully spiralling walk.

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