It goes down to the bottom of the ocean.

The waters of this placid subterranean lake are the brightest, loveliest blue that can be imagined.

They are as transparent as plate glass, and their coloring would shame the richest sky that ever bent over Italy.

No tint could be more ravishing, no lustre more superb.

Throw a stone into the water, and the myriad of tiny bubbles that are created flash out a brilliant glare like blue theatrical fires.