Numerous teeth thought to belong to a megalodon, a colossal prehistoric shark that could have eaten Jaws for breakfast, have recently been discovered in a flooded inland cavern. 

The numerous teeth were found by Kay Nicte Vilchis Zapata, diver and underwater photographer, in a network of water-filled caverns near the city of Mérida in Mexico’s Yucatan state, according to local newspaper The Yucatan Times. Known as Cenote Xoc, the main cavern is thought to run for over 600 meters (1,970 feet), with numerous smaller flooded vaults branching off the main corridor. 

Megalodon is the largest shark ever to swim in Earth's seas, measuring up to 18 meters (60 feet) from teeth to tailfin. The earliest megalodon fossils are around 20 million years old and the youngest date to around 3.6 million years ago, indicating these super-sized sharks dominated the world’s oceans for some 13 million years. 

Researchers assume megalodons effectively looked like scaled-up white sharks, but they are yet to discover a complete megalodon skeleton, so much of what we know about them is based on the shape and size of their teeth.

But what was a megalodon doing in an inland cave in Mexico? 

Like many parts of the world, this corner of Mexico was under the sea once upon a time. During the last hundreds of millions of years, Earth's sea level has undergone numerous dramatic rises and falls. Even within the past 15 million years, the golden hour for the megalodon, the planet has experienced notable sea-level fluctuations.

As a result, the remains of megalodon and many other extinct sea beasts can be found inland across the world. You can find the teeth of megalodons in parts of North America, especially at the bottom of creeks in North Carolina, South Carolina, and Florida. In fact, megalodon teeth have been found on every continent except Antarctica.

Prehistoric sea-level fluctuations also help to explain the bizarre geology of this area. The Yucatán Peninsula is home to dozens of cenotes, a natural sinkhole resulting from the collapse of a limestone roof. One of these cenotes – the longest known in the world – is a 347-kilometer (216-mile) labyrinth of underwater channels and passageways.

It isn’t just extinct sea creatures you find in these caves. Within the past couple of years, cave divers discovered the remains of a young woman who died 14,000 years ago, which makes her the oldest human skeleton ever discovered in the Americas. 

More recently, they even reconstructed her face using scans of the skull, forensic facial reconstruction techniques, and computer software.