Most of the buildings and structures in the Open-Air Museum are from the 18th and 19th centuries, mostly agrarian buildings made from wood. The oldest building is the Karuna Church, from 1686. The concept was to collect buildings typical of the different provinces and regions of Finland. At present there are 85 separate buildings in the museum, though few buildings have been added in recent years because the provinces have shown a desire to preserve such buildings as museums in their original location.