When talking about the Royal Palace it is very important to mention it is 1 room bigger than Buckingham palace. It is open to the public and you can visit one of the museum inside. You can also meet the royal guards that have been guarding the palace since 1523. The changing of the guards is also a popular attraction. They start at the Cavalry Barracks and than march to the Army Museum. They arrive at the palace around 12.15 (on Sundays around 13.15).
Royal Palace, Stockholm