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Update: Yucatan Peninsula, Mexico 2018

215 Miles connected!

              By National Geographic Staff
PUBLISHED JANUARY 17, 2018
Last Wednesday, after ten months of work, the Underwater Exploration Group of the Great Maya Aquifer Project (GAM) found a connection between two of the most extensive flooded cavern systems on Earth - Sac Actun and Dos Ojos, both in Mexico's Yucatán Peninsula—now forming the world's largest known flooded cave, with a length of 215 miles.
"This immense cave represents the most important submerged archaeological site in the world, since it has more than a hundred archaeological contexts, among which is evidence of the first settlers of America, as well as the extinct fauna and, of course, of the Maya culture," says Guillermo de Anda, a National Geographic explorer and director of the GAM.

Update: Yucatan Peninsula, Mexico 2009

This website is a legacy to the expedition of 1996, and reflects the design of the times, large text and table borders.

In the last 13 years there have been two other cave systems that are documented as being longer. So now the three longest underwater caves are all in the Yucatan. When someone swims through that hole that connects them, at least two will become one. The only question is whether the longest underwater system will become the longest cave on the planet, WET or DRY?

Update: Yucatan Peninsula, Mexico 2000

A huge new underwater cavern is being explored which is extraordinarily deep for the area. They call it simply "The Pit".

YUCATAN cavedive.com Logo

Yucatan Peninsula,
Mexico 1996

A Highly Decorated, Virgin Underwater Cave System was Recently Discovered. The Cavediver-Aquanauts push deeper and deeper into it. They've just exceeded 35 Miles of passages...a new world record...and there's more!

The World HQ of the
El Jacinto Pat Expedition Project.

This is NOT fiction,
It is History in the Making.


Maya Stone You are over the vast, flat, jungle expanse called the Yucatan.
Focus down on Tulum, the enigmatic, clifftop city of the Mayan Civilization.
The only Mayan city known to exist on the ocean's edge.

Maya Stone In the Jungles nearby the ancient city lie the Two Longest underwater cave systems known on earth.

Maya Stone The Mayan people, who continue to live and die here, regard the crystal clear holes leading to vast underground chambers as sacred. These are called Cenote, they are the doors to the underwater worlds.

Maya Stone Through a quirk of Nature, the liquid catacombs were once dry...Then they flooded, pristine and gorgeous, full of flowstone and stalactites, incredible beauty sealed in fresh, clear, glasslike water.

Maya Stone They found a skeleton in the now submerged caverns that could be 10,000 years old.

Maya Stone New Cave creatures that exist Nowhere else on earth are being found.

Maya Stone The Yucatan underwater cave systems continue to give up miles and miles each year to Mexico's total attracting world class cave divers. You can see them when you go snorkeling, because you are in a Cenote, like a large blue bathtub in the jungle and they come out of tubes at the bottom and climb out!

Maya Stone This is the official Internet HeadQuarters of the Brave souls who dare to journey to the farthest reaches underground, underwater, ever.

Locations of visitors to this page

Maya Stone Some of the fantastic letters from our visitors.


You Are at the Entrance

Field Headquarters Enter the MapRoom Explorers on the Expedition
Decorated Caves Tulum, Sea Cliff City

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