The group of researchers led by Polish diver Krzysztof Starnawski just completed an expedition to the underwater cave Hranická Propast in the Czech Republic to verify that this is the deepest underwater cave on Earth.
Since its first discovery in 1999 explorers tried to reach the bottom of the cave few times but only the most recent expedition sponsored by National Geographic managed to reach a depth of 404 metres (1,325 feet) using a remotely operated vehicle (ROV) which makes it 12 meters deeper than the second deepest underwater cave that we know of – Italy’s Pozzo del Merro.
Back in 2014, Starnawski thought he had reached the bottom of the cave at a depth of 200 metres (656 feet). During his next dive in the cave Starnawski ound an extremely narrow ‘squeeze passage’ that gave way to a gigantic, pitch black, vertical tunnel, which he tried to explore with a probe, but ran out of line at a depth of 384 metres (1,260 feet). Later on in 2015 the diver managed to stick a probe through last time had widened, which allowed him to actually swim through.
According to Long, during the most recent expedition last week, the team managed to use an ROV to fully explore the cave, verifying that it is, in fact, the deepest known cave in the world, at a depth of 404 metres (1,325 feet).
The Czech Speleological Society suggest the cave was deeper than 404 metres as the robot was as deep as its rope could go and the bottom was still nowhere in sight.
Check out the video below of Starnawski diving into the Hranická Propast last year:
All Images © Krzysztof Starnawski Expedition