After 20 years of exploration, this cave continues to take explorers further into the deep.

By Talia Avakian
September 30, 2016
Hranicka Proposes Exploring
Credit: Vimeo

The world’s deepest underwater cave ever discovered is a limestone abyss that goes down at least 1,325 feet in the Czech Republic.

Polish explorer Krzysztof Starnawski led the team that made the discovery at Hranická Propast, also known as the Hranic Abyss, according to National Geographic.

Starnawski has been exploring the location for the last 20 years, attempting to dive deeper each time.

A video from last year shows how Starnawki uses the robot in the cave.

To reach the new depths, the team used a remotely operated underwater robot to navigate down into the areas that are difficult to reach by diving.

Starnawski initially thought the cave ended at about 650 feet, but in 2014 he found a narrow opening leading to a vertical tunnel. He returned to the passage in 2015, and found it had worn away enough to allow him to dive through.

Starnawski told the Associated Press he felt like “a Columbus of the 21th century,” risking the challenging waters of the cave. He plans to again dive this Saturday and use the robot to see if he can go deeper.

Talia Avakian is a digital reporter at Travel + Leisure. Follow her on Twitter at @TaliaAvak.