Ice cave in the Skaftafell National Park in Iceland. Ice caves collapse and new ones form as each glacier grinds slowly towards the sea. Local guides can help you (without dying) find one. (Visit Skaftafell National Park in Iceland.
Secluded cave near Lagoa Algarve Portugal [Portugal is has it all. great food and wine sights natural spots (like this one) friendly people. and you can get away with your high school Spanish if you need to.
What may appear as a mirror image of the stars above, the bioluminescence in the water is actually due to marine microbes called phytoplankton. The effect it has on the shore is absolutely breathtaking. 27 Surreal Places To Visit Before You Die