A cave in the Czech Republic has just been crowned the world's deepest underwater cave. On Sept. 27, a Remotely Operated Underwater Vehicle (ROV) reached the bottom of Hranická Propast, at a depth of 1,325 feet. The team piloting the ROV was led by Polish diver Krzysztof Starnawski, who has been exploring the cave and attempting to hit rock bottom since 1999.