The Round Tower is a 17th-century tower in Copenhagen, Denmark, one of the many architectural projects of Christian IV of Denmark. Built as an astronomical observatory, it is noted for its equestrian staircase, a 7.5-turn helical corridor leading to the platform at the top, and its views over Copenhagen.
Rundetaarn
Rundetaarn. Illustration from the architect Laurids de Thurah's Hafnia hodierna of 1748.
Cross section of the tower and the church from Thurah's Hafnia Hodierna
The interior of the tower on a drawing by H.G.F. Holm in connection with his proposal to move the tower to a position next to the church
Christian IV was King of Denmark and Norway and Duke of Holstein and Schleswig from 1588 until his death in 1648. His reign of 59 years and 330 days is the longest in Scandinavian history.
Portrait by Pieter Isaacsz, c. 1612
Frederiksborg Castle, c. 1585.
At the death bed of Niels Kaas. The 17-year-old Christian IV receives from the dying chancellor the keys to the vault where the royal crown and sceptre are stored. History painting by Carl Bloch, 1880.
The coronation of King Christian IV on 29 August 1596 History painting by Otto Bache, 1887.