The Rosenkrantz Tower is Norway's most important landmark Renaissance building. It was once the residence of King Eirik Magnusson. It was converted into a gunpowder ammunition depot from 1740 to 1930 and was opened to the public as a tourist attraction in 1966. The oldest part of the building is the medieval tower, called "Keep by the Sea", built around 1270 and later expanded for military defense and other reasons. We went there and went to see the ticket along the old house in the port. The building includes an underground storage room, a ruler's residence and a top-floor turret that climbs up to the roof along the dark, stairwell. The order of the visits is not very clear, but no matter which room you see during the process of going upstairs, it is quite pleasant to stop and visit if you are interested. It is also fun to try on many old costumes and wear armor and weapons.