* Astronomy

The Rundetårn (English: Round Tower) is a 17th-century tower located in central Copenhagen, Denmark. One of the many architectural projects of Christian IV, it was built as an astronomical observatory. It is most noted for its 7.5-turn helical corridor leading to the top, and for the expansive views it affords over Copenhagen.
The foundation stone of was laid on 7 July 1637.
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