Akershus Castle and Fortress is one of the flagship destinations in Oslo. The fortress was first built in the thirteenth century to protect the city from invaders. It has withstood many sieges and still serves a reduced military function today. The castle features intriguing dungeons, crypts and a still-functional cathedral. Several museums are located on the grounds of the fortress, and tourists can see the changing of the guard daily. Though it might be closed occasionally for state functions, the fortress usually closes at nine p.m. Tours are offered several times a day during the summer and on a limited basis (usually Thursdays) during the winter. Call +47 23 09 35 53 for information on tours.
Address: Oslo mil/Akershus 0015 Oslo
Tel: +47 22-41-25-21