This floor to ceiling feature leftover from when water eroded out the passages of the cave that cave divers now swim through is a favourite of mine.
Tank Cave ice chamber
Local cave divers will know this room in Australia's Tank Cave by the inspirational name "90 Metre Room". I like to think of it as an ice chamber with a molten ceiling. It definitely feels icy on a smoking hot Australian summer's day!
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.
The world explored by cave divers
In the subterranean passages of Mexico's Yucatan Peninsula is an underwater world enjoyed by cave divers.
Calcite forms at the water's surface where there is contact with air. Below the air domes in cenote Nohoch Nah Chich, vast dunes of calcite have built up from the calcite settling to the cave floor over thousands of years.
String of Pearls
Harry Gust started exploring String of Pearls in 2006. Exploration was interrupted when the landowner closed access to the cenote during land disputes. The cave is open for diving again, under arrangement.
New GUE sidemount class
The diver training agency Global Underwater Explorers has a cave sidemount class for advanced cave divers (prerequisite GUE C2).
Sac Actun on sidemount
Sidemount is a versatile diving configuration that can be used to travel through very small cave passages, where backmount configuration may not be passable.