The world’s largest underwater cave has been discovered in Mexico

Uncovered in Mexico, and measuring 215.6 miles, the cave connects two of the world’s largest flooded caverns – Sac Actun and Dos Ojos in Tulum, Quintana Roo.

The Gran Acuifero Maya, the project behind the discovery, dedicated years of exploring the waters to try and find a connection between each of the limestone tunnels.

"This is an effort of more than 20 years, to travel hundreds of kilometres of caves submerged in Quintana Roo mainly, of which I dedicated 14 years to explore this monstrous Sac Actun System; now everyone's job is to keep it," Robert Schmittner, the German researcher and lead of the GAM exploration team, said in a statement.

"We came really close a few times," Schmittner told El Pais newspaper. "On a couple of occasions, we were a meter from making a connection between the two large cave systems."

"It was like trying to follow the veins within a body," Schmittner added. "It was a labyrinth of paths that sometimes came together and sometimes separated. We had to be very careful."

INAH investigator Guillermo de Anda has called the discovery "the most important underwater archaeological site in the world and home to hundreds of preserved secrets."

Indeed, the explorers have reportedly witnessed perfectly preserved artefacts showing evidence of the first American settlers and ancient Mayan civilisation.

The area was dominated by Maya civilization before the Spanish conquest in the 16th century and now, the team have discovered the remains of extinct fauna, early humans, Mayan archaeology, ceramics and Mayan graves.

Prior to this, the longest explored underwater cave was Ox Bel Ha system in the same region which measures 167.9 miles.

Currently, you can dive in parts of the system with a tour guide - fingers crossed, it won't be long until you can do the same in the Sac Actun System and make discoveries for yourself.