Rundetårn (The Round Tower)

Rundetårn is a 17th century building here in Copenhagen which is unique in that rather than stairs, it has a ramp (historically, to allow a horse and cart to carry books to and from the library situated adjacent to and accessed from the tower). It is the oldest functioning observatory in Europe.

Because Copenhagen is so flat, once you get to the top (about 35 metres above street level) you can see for quite a long way.