If you like deep cave diving, a place on your bucket list should be the Hranice Abyss in the Czech Republic.
Exploring the abyss has proven challenging for both divers and machines. A couple years ago an unmanned underwater rover was lost and subsequently found at a depth of 195 meters (640 feet).
The depth of the flooded part was recorded in 2016 to be 404 meters (1325 feet), with technical divers having reached a depth of 265 meters (869 feet) in 2015.
According to Michal Guba, who has led dive expeditions to the site:
“During the diving activity, new spaces are discovered irregularly, which will require further exploration. They are mostly deep and relatively narrow. However, none of the Hranice Karst speleologists doubts that interesting discoveries are still waiting for the Hranice Abyss.”
Speleologists are working to produce maps of both the dry and flooded parts from top to bottom, according to Guba, with photographic and video documentation to help refine the individual measurements.
For more info (with the help of Google Translate), check out the Hranicka Propast website.
(Image credits: Czech Speleological Organization)