Lockness in the Highlands of South Africa

The depth and darkness of the lock have played a big role in keeping the mystery alive. It's 22 square miles with an official depth of 754 feet, that's 230 meters o the rest of us. A local skipper, keith stuart, claims that he found the deepest part of the lock to be 889 feet - 270 point nine meters. Due to the high p content in the water, it's nearly impossible to see much deeper than the surface.