The Round Tower -- Copenhagen, Denmark

Completed in 1642, The Round Tower, or Rundetaarn, is the oldest functioning observatory in Europe.  It was used by the University of Copenhagen until 1861, but today anyone can view the night sky through the astronomical telescope in the observatory at the top of the tower.  

The Round Tower attached to the church and library

The Round Tower was the first building in the Trinitatis Complex built by King Christian IV linked to the University Church built especially for the scholars and students of Copenhagen’s University.

Building of the tower was inspired by Denmark’s astronomical achievements thanks to the astronomer Tycho Brahe, who died in 1601.

The 40-meter tall tower was built with a unique interior 210-meter long spiral ramp which leads to the top platform.  The whitewashed spiral ramp winds itself 7.5 times around the hollow core of the tower.

On the uppermost façade there is a gilded inscription, like a rebus, which may be interpreted: Lead God, the right teaching and justice into the heart of the crowned King Christian IV, 1642.  The original draft of this written in King Christian’s own hand is housed in the Danish Record Office.

One of Hans Christian Andersen’s fairy tales, The Tinder Box, written in 1835, tells the story of the soldier who meets the dog sitting on the money chests whose eyes are as big as the Round Tower. 

The spiral ramp to the top of the tower and the observatory

The ramp leads also to the library hall (its only entrance), which once housed the entire book collection of the university.  Andersen would visit here for inspiration for his works.  In 1861, the collection had outgrown the library and moved to its present location.  Restored in 1987, it is now used for exhibitions and concerts.

The two original privies still exist – one at the top and the other by the library, which has been restored but no longer in use.  You can actually go in, sit down, and have a look around the smallest room!

Although the spiral ramp is wide enough for an automobile, or horse and carriage in earlier times by Russian Tsar Peter the Great, today it ascended by foot – or by bicycle or unicycle at the annual race!  It is considered an easy climb with places to stop and rest along the way.

Today, a new attraction allows visitors to view the hollow core of the tower by walking on a floating glass floor 25 meters above ground.  The glass is 50 mm thick and can carry up to 900 kg per square meter. 

The center of the tower is from where all distances are measured in Copenhagen.  And the panoramic views are incredible!  Now enjoy a short video tour.