Blaafereveket, nice place to visit near Oslo

Blaafarveværket (originally Det Kongelige Modumske Blaafarveværk , later Modums Blaafarveværk ) is a former Norwegian mining company in Åmot in Modum in Buskerud that mined cobalt ore and used it for the production of cobalt blue , and is today a cultural and industrial history open-air museum and art gallery. Blaafarveværket was Norway's largest quarry and also Norway's largest industrial enterprise in the first half of the 19th century and is the largest and best preserved mining museum in Europe.