The Round Tower

Købmagergade 52A, 1150 København, Denmark

Walking along the winding streets of central Copenhagen, you will invariable chance upon the 17th-century Round Tower, with an observation deck that affords great views over the city and to Sweden in the distance. To reach the top, you walk up an interior spiral ramp with no stairs, designed to allow horses and carts in earlier times to ascend to the library and observatory, and today kids have great fun racing up and down the cobbles. The tower is also the site of an annual unicycle race. The record round-trip time so far: just under one minute 50 seconds.

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Finished in 1642, the Round Tower was constructed to serve as an astronomical observatory. The path to the top of the tower uses a sloped ramp in place of stairs, making for a highly unusual climb and fun experience. The top of the tower has a large viewing platform on it which allows scenic views of central Copenhagen. While not regularly available and subject to Denmark’s turbulent weather, each winter when the nights are long and the skies clear, they open the observatory to the public for limited evening viewings. As you can imagine, due to Copenhagen’s near-constant daylight in the summer, this isn’t available year-round.

Round Tower

The 17th century tower and observatory Rundetaarn, or the round tower, is the oldest functioning observatory in Europe.

When Christian IV built the tower, Denmark was quite famous for its astronomical achievements thanks to the astronomer Tycho Brahe. When he died in 1601, the King wished to continue Brahe’s research, and thus the round tower came into being.

It has been a while since the scientists left, but the observatory is still used by amateur astronomers and the many visitors. The observatory is encircled by an outdoor platform from which you have a magnificent view of the old part of Copenhagen.

To get there you need to walk up the spiral walk, which is 268,5 meters long at the outer wall and only 85,5 meters long close to the core of the building. This means that you walk around 209 meters to get to top even though the tower is only 36 meters tall.

The tower from inside

This walk also leads to the library hall, which once housed the entire book collection of the university. The famous Danish writer H.C. Andersen used to visit the library and he found inspiration for his work here. Today the hall serves as the framework for exhibitions of art, culture, history and science.

Floating glass floor

As a new attraction you can now see the tower’s core by standing on a glass floor, hovering 25 metres above the ground. The glass is more than 50 mm thick and can carry up to 900 kg per square meter.

Information on this page, including website, location, and opening hours, is subject to have changed since this page was last published. If you would like to report anything that’s inaccurate, let us know at

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