Off to Tulumby Cl. Panic, fresh water guest blogger

While Ms. Nu is in for some disappointment, the rest of the readers are in for a treat. I received a demand for more pictures of fish. Any fish. Problem is there were no fish to speak of today. Why? We dove in the middle of dry land. Now, you're probably asking yourself, "Did Cl. Panic eat the worm, because that's crazy talk!" Well, my friends it's not the worm talking. We took a trip to the mainland for some cenote diving.

To get there, we drove into town, hopped on a ferry to Playa Del Carmen (how would you like this guy's job?), hired a bicyclist to carry our gear to a van, and were then whisked off to the dive site.

What the hell is a cenote? Glad you asked.

Much of the Yucatan land mass used to be under water. Sediment from dead ocean-things, combined with coral "skeletons," pelagic ooze, and other such goodies formed into layer upon layer of limestone. At some point the limestone rose above ground to form the happy land masses that we now know and love as Cozumel, Cancun, and other tropical paradises.

Limestone, or calcium carbonate for the chemists and geologists in the house, isn't the most stable of materials. Like the Wicked Witch of the West, limestone is ready for a meltdown. Just the slightest bit of acid, and limestone will dissolve. In fact, rain water and ground water can either dissolve limestone, or precipitate it, depending on the pH of the water.

Over millions of years, water and the elements wore away at the limestone and created a series of underground caves, caverns, and natural canals. A series of underground rivers still exists throughout much of Mexico, and still form a primary source of drinking water for many people. As the water table rose and fell, the stalactites and stalagmites formed. Occasionally, the roofs of the caverns break free, creating sinkholes -- entrances to the cenote systems -- usually in the middle what would otherwise be semi-desert.

In fact, the Mayans built Chitzen Itza near a cenote, which they believed to be a portal into the other world. They even tossed a few people in there for good luck.

We dove a cenote called "dos ojos." If you really look at the panoramic picture above, you can see why: there are two entrances, and they look like eyes beneath the surface of the water. That's right, the innocent looking swimming hole is actually a portal to the underworld! In this case, the underworld consisted of crystal-clear fresh water that was somewhere around 75 degrees.

The diving in dos ojos was simply amazing. The water was so incredibly clear, it was like diving in air (maybe clearer than if you dove in the air of Los Angeles). Really, it was like we were floating. Even though dos ojos is a cavern system and not a cave, it was still dark and hard to photograph. For a first-timer, it was a great site, as the systems was nice and wide, and a line guided you through the system in a loop. Our guide warned us that there was an alligator at the half-way point.

We ended up doing two dives at dos ojos. On the second dive, we surfaced in the bat cave. Yes, there were actual bats. They were really hard to get in a picture, but trust me: there were bats.

We all got out safely, in spite of a some rather ominous warning signs, thanks in part to the fantastic guides that escorted us through dos ojos. Once back in Cozumel, we were treated to a fantastic sunset and then headed for an awesome dinner at El Moro, which happens to be Cl. Panic's favorite restaurant on the island.

After an fantastic dinner and a Mayan Sacrifice, sleep was not too far behind.