Just after the last ice age, when the massive ice sheet started retreating, Botsmark was at the shore of the Gulf of Bothnia. The rapid land uplift that followed left some distinct geological traces. The granite caves in the scree of the hill Stor-Boberget were formed by a violent earthquake in the year 7341 BC, when the southern slope collapsed in a gigantic rock-slide. You will find five caves, up to 120 metres long, below and between the rocks. You can reach the caves by an appr. half hour walk through the forest from Botsmark village.
More information here.
BEWARE: The walk along the trail is done strictly at your own risk!