Carlsbad Caverns National Park preserves one of the oldest and most famous cave systems in the world. Deep beneath the Chihuahuan Desert in southern New Mexico is a labyrinth of more than 300 limestone caves, carved over 250 million years ago. The primary attraction of the park is the show cave, Carlsbad Cavern, that includes a large cave chamber, called The Big Room. It is one of the world's largest cave rooms, with unusually extensive and diverse decorations. It is a natural limestone chamber almost 1220 meters long and 78 meters high at the highest point. The park is found where the plains of the Chihuahuan Desert meet the Guadalupe Mountains. The park also preserves biologically diverse desert lands above ground, as well as a portion of an exposed fossil reef.