There is a lot of limestone in the Northeast section of Gotland. on the south part of the island it is sandstone. You will find old broken and closed limestone factories but there is still one working in Slite. Eventually, as more and more limestone was taken from the earth there would come a point when the mine would fill up with water.
These quarries are deep and the water is very clear and turqoise, just like one might find in the Caribbean. The most famous quarry is called The Blue Lagoon. In the summer it is crowded with people swimming and sunbathing.
