Gaustad gruve was a jerngruve located on the east side of Vettakollen, just north-east of Sognsvann. It was open from 1538-1580 and 1792-1854, operated by Morten Krabbe and Peder Anker respectively, and it delivered jernmalm to Bærum’s Verk. The stollen (a man-made tunnel) is now open for visitors and can be explored for an interesting adventure! Visitors should also note that the magnetite-rich slag in the area can interfere with compasses!