Gnäggen barely protrudes above the waters of the Gulf of Bothnia, and but for the scattering of willow, rowan and aspen trees that try to grow in the cracks between the rocks, one could be forgiven for thinking that the whole island is regularly wave-washed. In fact this dolerite speck a few kilometers off the Swedish coast was smoothed by the action of ice sheets during the last Ice Age, and like many of the land forms in the region has been rebounding upwards since the great weight of ice melted away.