MEMEZILLA on Instagram: "Here’s an interesting fact: Cave diving is considered one of the most dangerous types of diving because divers can’t swim straight to the surface in an emergency. Instead, they must carefully follow a guide line back through narrow, dark underwater tunnels, sometimes hundreds of meters long. If that line is lost or visibility drops to zero from stirred-up silt, divers can become completely disoriented in total darkness. That’s why cave divers train extensively and carry