Akershus Slott (castle) and Festning (fortress) were built to protect the city from the various invaders, warrior tribes, plunderers, enemies, foes, cretins and other unwelcome guests who dropped in from time to time. The two buildings appear as one in this photo, taken from across Oslo Harbor. Construction began in 1299, but like many medieval buildings, this one has been rebuilt and renovated numerous times due to fire, war and natural deterioration. Despite its many facelifts, Akershus Slott remains an imposing structure. It’s one of Oslo’s most recognizable buildings and popular tourist stops, and it continues to serve as a military installation.