History is filled with numerous unsolved mysteries that modern humans need time to understand. In the movie called The Descent, a group of girls goes to explore a cave but gets trapped inside by inhuman creatures and twisted cave paths. But in reality, the story is different altogether. Two cavers have successfully found 15,000-year-old ice age cave networks beneath Montreal city located in Canada.

Luc Le Blanc and Daniel Caron went to explore the ancient cave network in October 2017. They first heard about the existence of the cave in 2014, got to know that it is 650 feet long. The original cave was explored in 1812 which is located under a city park and eventually became a famous tourist spot.

Although nearly 3,000 visitors go there, no one had passed the fissure until Le Blanc and Caron took the initiative to explore the rest of the cave by using their tools. Le Blanc, who has 40-years of experience in the field of adventure sports, told Newsweek that compared to the original cave the newly discovered channel is "bigger, higher, wider and more beautiful because it's remained pristine."

During the exploration process, the cavers discovered one direction circle, which is linked to the main cave entrance. There was another lead which was almost filled with water. Although the explorers used inflatable canoes and swam to move forward, they still failed to find the end of the cave tunnel. Le Blanc explained, "We stopped when our helmets were rubbing the ceiling."

This is not the first case of underground discoveries, though.

A book entitled Secrets Of The Underground Door To An Ancient World by German archaeologist Heinrich Kusch, had revealed that stone age men had created a huge underground tunnel from Scotland to Turkey, which was used as a communicative highway.

Beneath Paris, lies another example of centuries-old underground tunnel, which is filled with millions of skeletons. This is called the Catacombs of Paris. Even though this place is open to the visitors, most of this weird tunnel could not be explored.

In Turkey, there are 36 underground cities in Cappadocia, including a mysterious underground city of Derinkuyu. In 2014, a housing project team had accidentally discovered the entrance to these strange caves. These caves led them to long wide tunnels which finally helped to uncover the underground city of Cappadocia.