Stalactites are icicle-like rock formations that hang from the ceilings of caves. They're one of the delicate formations that we need to dive most carefully around when cave diving.
Bringing light to the dark
Away from the cavern zone, underwater caves exist in perpetual darkness, lit up for mere seconds as cave divers pass through.
A slab of rock that was once part of the ceiling lies like a giant altar on the road through Mexican cave system Sac Actun.