A massive underwater sinkhole off the coast of Mexico has swallowed every instrument scientists have lowered into it, and they still have no idea how far down it goes. The Taam ja’ Blue Hole, sitting ...

From the air, it looks like an ink spill in turquoise water, a perfect circle that seems to drop straight into the planet. For decades, Belize’s Great Blue Hole has pulled in explorers, filmmakers and ...