Russian divers working for the Orda Cave Awareness Project have revealed stunning images of the world's longest underwater cave.
posted by bwg on Jul 12, 2011 - 38 comments

"ALL U-BOATS. ATTENTION ALL U-BOATS. CEASE-FIRE AT ONCE. STOP ALL HOSTILE ACTION AGAINST ALLIED SHIPPING. DÖNITZ." [more inside]
posted by AugieAugustus on May 6, 2011 - 42 comments

Lake Kaindy is a lake in Kazakhstan that was created after a huge landslide. A portion of the surrounding forest was submerged, and has since become regionally famous for its underwater trees. The coolest pictures, by far, are from the guys who went ice diving in the middle of winter.
posted by shiu mai baby on Jul 15, 2010 - 18 comments

Underwater Basejumping. That is all.
posted by allkindsoftime on Jun 5, 2010 - 49 comments

And here I am kicking my own legs like a sucker. From DEKA Research the folks that made the Segway and DARPA the little defense department that could (bomb you) comes Power Swim which uses an oscillating foil to develop vortices that...uh, it makes you go faster in the water. Some pictures, here. [more inside]
posted by Smedleyman on Dec 19, 2007 - 27 comments

Underwater Tigers. Best one.
posted by milestogo on May 14, 2007 - 73 comments