Blue Grotto

Most of them are semi-submerged caves facing the sea, and it is possible to enter the inside through a limited entrance.
The sea of this cave is much more beautiful blue than usual, and the surface of the sea looks like it shines blue.
It seems that the cave generation will change significantly with the update on the cave in Minecraft, but if you add this "blue cave", the cave will give you a horrifying and mysterious impression.
If you have any other good ideas, let us know in the comments.
Thank you for taking a look at my thoughts.