This big rock east of Kalvsviks Farm and 50 meters up in the forest from Kalvsviksvägen is known as Vargklyftan (wolf's rift or cleft) or Kalvsviksstenen (Kalvsviks Stone). It has been perfectly split into two parts. It is five meters high and you can walk through it. If you do you will go mad or disappear...(I have walked through it!). No one knows for sure what happened and when, it could be a remnant from the ice age, it's not very likely that lightning struck the stone ,it's simply too big.