It's early. The sun begins to peek over the horizon of a cloudless sky. Although it looks as though it will be a bright, beautiful day, it doesn't matter much whether it rains or shines because I'm going to descend nearly 1,000 feet into the earth's crust for a subterranean sojourn in a realm of gigantic crystalline rock formations never touched by the rays of the sun. Over 30 miles of caves have been discovered in the Carlsbad system, including a 14-acre room large enough for a professional baseball game. Incredibly, this enormous underground domain was formed by simple groundwater - drip after tiny drip.