A few years ago I went with my family to Capri, Italy. We took a boat ride on the Tyrrhenian Sea and came to a small hole, which served as the entrance to a cave. In order to make it into the cave, we had to take a smaller boat. The waves would fill 3/4 of the hole, so our timing had to be perfect. Fortunately, the man who rowed had tons of experience and we made it through the gap just as the water started to rise again. When we entered, the shadow of the cave from the outside was replaced by an incredible glow. Somehow the sun reflected off the walls and the water to create a reflection of shimmering blue light. We jumped in and the water felt no different than it was outside. From there we could see the water radiate onto the people in their boats. After climbing back in and coming out of the cave, everything seemed a lot more bland. It took a while for my eyes to adjust after seeing such an astounding sight.