As humans, we all want to push ourselves to the brink.

For that reason, sports pioneers found new ways for us to experience the adrenalin rush that is living right off the edge. Put another way, cheating death to achieve a crazy altitude, a G-force inducing speed or vertigo-inducing thrill ride is what many crave.

Rock climbing (not on this list) gained popularity in the ’70s as an “extreme” sport. Since then, avid climbers have pushed the limits of gravity to scale vertical formations, some of them at greater than 90-degree pitch. Clinging to a face with pitons and crampons, gaining toeholds and handholds, climbers put their bodies and lives at great risk. Careful climbers use ropes and safety harnesses, but the truly extreme free-climb, using nothing but their strength and balance to grope their way to the peak.

The most extreme sports, therefore, involve activity with injury and even death always in the mind of the participant. Here are 5 extreme sports that really are extreme.

5. Ice Climbing

This is the more death-defying and challenging of the climbing sports, in that ice formations are less reliable than rock. It can be either soft and bitter, or hard and tough. The differences lie in the equipment and grading system for ice formations. Climbers use ice axes, sharp pitons and crampons and ice screws to anchor themselves in. Climbing waterfall formations has its own grading system, and is generally used for mixed ice formations as well. Waterfall Ice (WI) grade 2 is the most gentle grade at 60 degrees of consistent ice. The grading system then goes up to WI5 (near vertical) all the way to WI7, which has overhang and is thought to be a near mythical grade. The danger or extreme factor, of course, can be measured against recorded deaths. This year in Pemberton, British Columbia, three ice climbers plunged to their deaths on Joffre Peak. Even though they had all the appropriate gear like harnesses and were roped in together, it didn’t prevent the fatal fall.

4. Surfing

Shooting the curl of a giant wave has so many dangerous elements, one has to wonder why people surf at all. That, though, is the attraction for “grommets” (young surfers), to hodads (posers) to the Laird Hamiltons of the world. From Australia (Crescent Head, Seal Rocks), to Teahupo’o to Hawai’i (famous Pipeline), to points all over the globe surfers ride gnarly swells, hanging 10 and trying to avoid being ragdolled on sharp coral reefs. The dangers to humans riding long and short boards include (but aren’t limited to): marine life (ie sharks), drowning, riptides, their own boards (getting hit by it), the sea bed (and the aforementioned razor sharp coral) as well as crowded waves and “Stu’s” (newbies). If you need any more proof that surfing is one of the most extreme sports around, look no further than the deaths of some of the most experienced surfers found on the planet. Donnie Solomon drowned after getting midway up the face of a “bomb” (huge wave) at Waimea and getting caught underneath it’s tons of water. Tahiti’s Malik Joyeux, a true professional, drowned at Pipeline after the lip of a giant wave hit him over the head and knocked him unconscious.

3. Downhill Mountain Biking

The sport of mountain biking requires immense skill, endurance and tactical know-how. Enthusiasts and participants pit themselves against each other and the elements in cross-country and trail-riding. The Union Cycliste Interntionale organizes many professional events, including Olympic level. But, somewhere, someone had the bright idea that racers should just race uphill, but down it. Crazy, right? Sure, downhill riders have more rigid bikes with better suspension and brakes and they wear helmets and body suits, but the routes chosen can kindly be called treacherous. Riders must negotiate steep pitches, jumps of up to 12 feet and dramatic drops, as well genuinely rough, scraggy terrain. You would be hard-pressed to find a downhiller who hasn’t experienced at least one catastrophic injury. Worse yet, the Grim Reaper is never very far away. Matt Klee, of Hood River, Oregon, was a very experienced downhill rider who died last year after crashing on a rock formation at Whistler Mountain (B.C.) Bike Park. It was the second such death at the same park, highlighting the extreme nature of the sport.

2. BASE Jumping

BASE (Buildings, antennas, spans and earth) jumping isn’t just dangerous and considered a fringe sport, but also illegal in most countries. Those that dare plunge from man-made and natural features not only have to avoid the pitfalls of faulty parachutes and lethal crosswinds but must steer clear of the long arm of the law after having done so. Intrepid parachutists have leapt off some of the earth’s most famous locales, including El Capitan in Yosemite, The Eiger in the Swiss Alps, the Perrine Bridge of Snake River Canyon, Idaho, the Burj Khalifa in Dubai and even Millenium Stadium in Cardiff, Wales. One of the most famous BASE jumps ever was made by construction worker Bill Eustace, who sailed off the CN Tower in 1975 when it was under construction. He was fired for his stunt. The evolution of the wing-suit has made BASE jumping safer, but statistics about just how deadly the sport is don’t lie. As of this writing, there have been 251 recorded BASE jumping deaths since 1981.

1. Sky Diving

BASE jumping is one thing, in that it is done from typically lower altitudes, but free falling from a plane at 13,000 feet (the outer limit) is quite another. The old saw goes, “why would anyone jump from a perfectly serviceable aircraft?” definitely applies. We ask, “ya, why?” Because it’s the most dangerous and death-defying, but also the most exhilirating of any extreme sport. Taking the leap of faith and soaring through the air fulfills the first-timer’s feeling of what it is to truly “fly.” With advances in equipment and better training, skydiving has become quite a bit safer over the years. But skydiving “safety” is still a misnomer. The U.S. Skydiving association has state that there are “only” 21 deaths per year, or about one for every 150,000 jumps. Those odds aren’t bad, but would you want to be the 1 in 150,000 who bites the earth at up to 200 mph? We think not. There have been 648 recorded fatalities world wide since 2004 (statistics available up to 2014).