Oh, there have been SO many good ones . . . but so far, the best was last Saturday. We went to Pet Cemetery, which is a place I hadn't been before. It was a lot of work to get the equipment down to the water (and even more, as always, to get it back UP) and the people we went with, who had dived there last year, got a bit confused about how to find the mainline, so we spent a lot of frustrating time swimming around and not getting anywhere. (It's an easy place to do that, because there is a tremendous amount of open water under a rock roof before you get to where even the cavern line runs. We spent over 20 minutes looking!)
But even the search was beautiful, with sunlit rooms and heavy decorations everywhere, and once we started into the cave, it just got better. This cave is very white in most places, with a lot of decorations, some of which are delicate and some of which are more massive. The character of the passage varies, opening into large rooms and closing into defined, phreatic tunnel. Once we got on the Diaz line, there were some fun technical challenges (the "King Pong" restriction being one of them) but they were isolated enough so that the dive was not fatiguing.
Not quite an hour into the dive, the passage suddenly gets shallow, and the decorations become heavily stained with tannin. Off to our right was an area of deep gloom, and the line turned that way. We followed it, and suddenly, the world fell away beneath us, and we sailed out into an almost inconceivably tremendous space. The line plunged beneath us, and as we descended, my light sometimes could not even pick up and define the walls around us. The water became the deep, royal blue of spaces below the halocline. One of my buddies shot a picture of me giving the "shaka" sign at this point, and I look stupidly intoxicated in the photo, because I was.
One of the essences of cave diving, to me, is "What's around the corner?" Sometimes, it's just more of the same (which is not a BAD thing), but sometimes, it's unexpected and amazing.