Scientists haven't been able to reach the bottom.

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 ...

Blue holes are among the least understood features of the ocean floor. From the surface, they can appear ordinary, even calm, blending into the surrou.

The Taam ja’ is blue hole is still defined by what we don’t know. We can say it’s deeper than 1,390 feet, and the bottom hasn’t been found.