Sporting a copper roof and surrounded by moats, Rosenburg Castle in Copenhagen houses the royal crown jewels and acts as a museum of the Royal Family. It was built by Christian IV (1606-1634) in Renaissance-style as a royal summer residence.
The Royal Danish chronological collections here include silver, china and paintings, but the greatest attractions are the crown jewels and the crown regalia in the treasure vaults. Each room represents a different period, beginning with the Renaissance, followed by the Baroque period, continuing right up to the time of Frederik VII. If you want more, nearby Amalienborg Palace houses the remainder of the Chronological Collection - from Frederik VII to the present day.