The Rundetårn (Copenhagen, Denmark)

The Rundetårn
Photo by Peter Leth

The Rundetårn (literally the round tower) is a 34.8 m high tower with a smooth slanted spiral corridor instead of stairs. The 209m (964 foot) long spiral ramp winds itself  around the hollow core of the tower seven and half times. Built by King Christian IV between 1637 and 1642, the Rundetårn was the first part of the Trinitatis Complex, which combined a church, a library, and an observatory into one large complex.

The building, designed by architect Hans Steenwinckel the Younger remained in use as an observatory until mid 19th century when light pollution and vibrations from the city made accurate observations impossible. The lack of stairs was an idea of the builders that made it easier to carry the heavy astronomical equipment up to the top of the tower.

Since it was no longer able to be used as an astronomical tower, the unique design of the structure segued nicely for the next stage of the building’s life. That next stage of the buildings life was of course racing up and down the spirals with various vehicles.

A unique feature of the tower is that it contains a toilet once used by researchers and astronomers working in the tower. The crude toilet is a single shaft leading down from the top of the building to the bottom floor. Since there is no ventilation to the outside and no plumbing, it was essentially a giant septic system and is thankfully no longer in use.

The Rundetårn Facts

  • In 1726, emperor of Russia Peter the Great ascended the corridor on horseback.
  • The first bicycle race in the tower was organized in 1888.
  • The round tower is still used by amateur astronomers wishing to view the night sky.
  • In 1902, a Beaufort car was the first motorized vehicle to ascend this tower.
  • The current bicycle record is 55.3 seconds and was set in 1993 by Ole Ritter in a race against Leif Mortensen.
  • The upper portion of the main facade is decorated by a gilded rebus, designed by King Christian IV himself.
  • In 1989, Thomas Olsen went up and down the Rundetårn on a unicycle in 1 minute and 48.7 seconds.