Giola Lagoon/Thassos-Greece The Giola is a beautiful natural lagoon, like a swimming pool carved into the rocks. The water is warmer than the sea, which makes it pleasant for swimming. The place is unknown and the access there is difficult.
The deep blue Crystal Cave of Svmnafellsjvkull (CORR) in Skaftafell, Iceland was created by the glacier from Vrffajvkull Volcano's icecap meeting the coastline. The deep blue color is due to centuries of compression removing air from the ice.