The Castle of Rosenborg is located in the very center of Copenhagen. The castle was originally built in 1606-1607 as a summerhouse ordered by Christian IV.

You can tour the entire Castle and get an idea of how the Royalties used to spend their summer vacations.  In the last section of the Castle you are able to see the treasures Crown jewelries. 

A fun fact is that Amalie's 3 x great grandfather designed a set of Crown jewelries that are actually displayed in the castle.

For free you can also tour the cute Castle garden which offers beautiful views to the castles architecture.