Although there is vanishingly little ancient architecture to visit in Oslo, Vøienvold Farm is a relatively intact 17th century farmhouse, its outbuildings, and a small garden, mostly re-built in the local vernacular style in 1917. It is now home to several offices for nonprofit organizations, and may be rented out for private events. Most of the time the grounds are open to visitors seeking a quiet moment in the gardens, or for viewing the historical architecture from the exterior. Definitely worth a few minutes of your time if you are strolling up Maridalsveien. It is only a pity that this little pearl, hiding in plain sight, is not used more frequently for public events. A (Norwegian language) description of some of the buildings is available on the Oslo Fortisminneforeningen website.