Cliff diving from any height can be unsafe — it's one of the most dangerous extreme sports. In fact, official tourism sites of popular cliff diving destinations don't promote the activity.
Cliff diving puts tremendous stresses on your body. If you jump from 20 feet (6 meters) above the water, you'll hit the water at 25 mph (40 kph) — the impact is strong enough to compress your spine, break bones or give you a concussion [source: Glen Canyon Natural History Association]. But that's only if you enter feet-first in a straight, vertical line — a horizontal, or "pancake," landing is like hitting concrete. Halving the height of the jump to 10 feet (3 meters) reduces your speed of impact to 17 mph (27 kph), and even cars sustain damage when hit at that speed.
Because of the high potential for injury, the World High Diving Federation recommends that no one dive from 20 meters (65.5 feet) or higher unless there are professional rescue scuba divers stationed in the water [source: World High Diving Federation]. Bruises, dislocated joints, broken bones, compressed spine, injured discs, and paralysis are among the injuries that cliff divers experience. Death is also a possibility.
Competitive cliff divers free fall from heights of 59 to 85 feet (18 to 26 meters), but professional show divers in Acapulco, the La Quebrada Cliff Divers, sometimes jump from 148 feet (45 meters) above the water [sources: World High Dive Federation, Red Bull Media Service, Vacations Made Easy]. These show divers survive to dive another day because of their years of training, familiarity with the area and their ability to adjust their dives according to fluctuating wave and water conditions. But even they occasionally sustain injuries.
The WHDF considers water depths of 43 to 49 feet (13 to 15 meters) adequate for dives from 65 feet (20 meters) or less, but water clarity is also a critical factor for cliff-diving safety. Hitting the water badly from a height can cause injury, but hitting something in the water — a rock, a branch, the bottom, even a fish — or the water body's floor can be fatal. Choppy waters and high waves often obscure the surface of the water and interfere with the precision of entry, but world champion cliff diver Orlando Duque says that waves break the surface of the water and soften the impact. Entering the water on the peak of a wave shortens the dive, and you must complete any acrobatics early in the dive so you can get your body into the proper position for water entry.