In the 17th century, Christian IV renovated Akershus Castle into a Renaissance palace, although the front remains decidedly medieval. In its dungeons you'll find dark cubbyholes where outcast nobles were kept under lock and key, while the upper floors contained sharply contrasting lavish banquet halls and staterooms.
The castle chapel is still used for army events, and the crypts of King Håkon VII and Olav V lie beneath it. The guided tours are led by university students in period dress and, while not compulsory, they do offer an entertaining anecdotal history of the place that you won't get by wandering around on your own.
