Aaron E.
Google
Forget blue grotto, go here instead!
10€, no wait time, free parking and half an hour on a rowboat in the cave.
The guide Ernesto said to not forget him, so I don't. He was joking around and showing the best details, and speaks the most important words in most languages with good english. Go here, get on a boat with him, and see the blue shimmer through the water!