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 HÃ¥kon VII and Olav V lie beneath it. The castle is currently closed to the public for renovations.