It is called the Hranice Abyss (or Hranicka Propast in Czech) and it has now been confirmed as the world’s deepest cave. The Hranice Abyss is located in Hurka u Hranic nature reserve in the eastern part of Czech Republic, around 300 kilometers from Prague.
The 48-year-old explorer himself dived into the abyss to measure its depth. Starnawski dived as deep as 200 meters from which point he sent an underwater robot tied to a cord.
The robot dived to a depth of 404 meters but did not hit the bottom indicating that the depth of the fissure is more than that.
The Czech Speleological Society said, “It was as deep as its rope could go, but the bottom was still nowhere in sight.”
The temperature of the water is as low as 15 degrees Celsius
Starnawski’s team released a cross-section map which shows the fissure but ends with question marks at the bottom because the exact depth is not clear yet.
National Geographic covered some of the expedition’s cost.