This swimming pool in Mumbai, India, has been built to raise awareness about the threat of sea level rises as a result of global warming. It was constructed by attaching a giant aerial photograph of the New York City skyline to the floor of the pool.
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.
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.
I'm an avid scuba diver. Ever the domain of the wealthy, scuba diving required both access to the ocean and a shite ton of money for travel & equipment. Not really having any of it, this awesome hobby just kinda passed me by.