It's hard to tell one rocky plateau from another. Plus, the dark cave entrance that eventually leads to the treasure is surprisingly well-hidden if you're moving fast. Finding The Blade that ...

But finally I hoisted myself up a 450-foot rope to the cave’s main entrance (dubbed Izhevskaya, or R21). I began to see why cavers think of Dark Star as a living, breathing entity. Down at base ...

When something goes wrong, if they don't solve the problem and make it back to the cave entrance before their ... of the inland blue holes—deep, dark, sheltered, with little tidal flow ...