Here you are, Michelle:
The Round Tower was originally built in 1642 by Christian IV of Denmark, as an astronomic observatory.
Although there are 209 metres of stairway to the top of Rundetårn, the building itself is only about 35 metres high.
Guests ascend an endlessly spiralling staircase ,which twists itself around the hollow centre of the tower seven and a half times. As you slowly but surely make your way towards the top taking in the beautiful panoramic view of the medieval city, spare a thought for those who have gone before you.
In October 1716, the Czar, Peter the Great, rode his horse to the top. His wife, Katarina, made the same journey in a lightweight two-wheeled carriage. Whether it was laziness or sheer imperial contempt for Danish cultural customs remains unknown.
Today, people of all ages visit the tower - tourists and kindergarten children alike. Each year nearly 400,000 people crawl, walk and run up the tower, not to mention those who cycle to the top. Once a year, a unicycle race is held. Participants have to cycle up and down without making any mistakes and without dismounting once. The tower's concert and exhibition rooms offer a wide variety of classical concerts and art exhibitions.
You can read more about it at The Round Tower site.