Calavera means “skull” in Spanish and gets its name from the shape of the three holes that lead into the water. When seen from below, the sunlight passes through the holes giving the illusion of two eyes and a mouth. This cavern is very large and an amazing dive. There are a few sections in the cavern where you will swim through a halocline. A halocline is where two separate layers of salt and fresh water touch. These waters will not mix unless they are disturbed, resulting in reduced visibility (similar to the back of a jet at the airport). There are plenty of fossils at this site, making it very popular among local divers.