Below the surface of the Earth

where is this?

The sign is there for a reason. Untrained divers could easily get lost in the caves or be swept away by a strong current inside of one. Not to mention that cave walls can be very sharp meaning that the slightest mistake could easily incapacitate you. It looks pretty and all, but I'll repeat it: The sign is there for a reason.

In case you don't want to zoom in: "Stop. Prevent Your Death! Go No Farther. Fact: More than 300 divers, including open water suba instructors, have died in caves just like this one. Fact: You needed training to dive. You need cave training and cave equipment to cave-dive. Fact: Without cave training and cave equipment divers can die here. Fact: It CAN happen to YOU! There's nothing in this cave worth dying for! Do not go beyond this point."