Going round and round and round
This tower is just funny, it was constructed by king Christian IV and he wanted to be able to ride on his horse to the top of the tower. So that means: no stairs, just the floor spiraling all the way up. From the top there's lots of place to enjoy the fresh air and the view over Copenhagen.
The planetary observatory on the top is occasionally open for the public.
Trivia fact: H.C. Andersen's fairy tale of the Witch and the Soldier refers to this tower: the third dog in the fairy tale is described as having eyes as big as Copenhagen's Round Tower.