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Prehistoric Scratchpad

The largest underwater cave network in the world in the Yukatan Peninsula of Mexico. Filled with prehistoric animal remains and paleoamerican and mayan fossils and artifacts.


10,000 Years Ago[]

This cave system was submerged under water. Sinkholes leading to the surface were a trap for animal life to fall into. Paleoamericans lived above the caves and occasionally also fell into them. They had been in the region for at least 3000 years and had come from Berengia near Alaska.

Earlier History[]

These caves were originally created during the impact of the meteor that struck the Yucatan Penninsula 65 million years ago, which had wiped out the dinosaurs.

During the ice age, animals would enter the caves, as would humans looking for water. These included cave bears, saber-toothed cates, pumas, sloths, gomphothere (elephant), and bobcats. When the sea levels rose near the end of the ice age when the ice melted, the cave became submerged in water, preserving the fossils.

12 or 13 thousand years ago, a paleo indian girl who would be later called Naia fell into one of the sinkholes and died. Her skeleton would later be found by divers in 2007 and be be described as the "oldest, most complete and genetically intact human skeleton in the New World". DNA analysis would confirm that the Paleo-Indians of this era were the ancestors of the Mayan people and had migrated from Berengia near Alaska. A male from about the same time period also fell in, but his bones would be looted after they were discovered.

Later History[]

A human would also fall in about 9000 years ago.

When the Mayan civilization developed, the sink holes of this underground waterway would be considered gateways to the underworld. It was thought to be the domain of gods and the Mayans would give them offerings by throwing sacred items and possibly human sacrifices into them. These items were later recovered in modern times during scuba diving expeditions. The entryways near the coast were used as a pilgrimage site for travelers and merchants. The Mayan port city of Zama ("City of Dawn", modern day Tulum) was built near it. This was heavily fortified and obtained its water from one of the sink holes. It continued to be occupied until the Spanish arrived.

Modern History[]

The caves were discovered in 1989 by two american divers-speleologists. Remains of Naia were found in 2007. In 2018, a link to the Dos Ojos cave system was found, and the two systems were combined, making this one the longest in the world.


These caves are among the most popular skuba-diving destinations in the Yucatan and in the world. One of the primary entry points is at Tulum, Mexico.

Sistema Sac Actun Web Pages[]

Sistema Sac Actun In the News[]

Naya's DNA Shows She Was Related to Today's Native Americans and Siberians (May 2014)[]

One of Oldest Skeletons in Americas Found and Looted (Sep 2017)[]

Becomes World's Longest Known Underwater Cave System (Jan 2018)[]

Ice Age Animal Fossils, 9000 Year Old Paleoindian remains, and Mayan Artifacts Found (Feb 2018)[]

Threatened By Pollution (Feb 2018)[]

Mayan Pilgrimage Site Found (Mar 2018)[]



Divers discover 215-mile-long cave in Mexico full of Mayan relics


Riviera Maya Excursion Tulum - Cenote Sac Actun - Akumal

Google Earth[]