NOT TOO LONG AGO, rock climbing was a relatively unknown and uncelebrated sport. Relegated to a small group of dedicated and eclectic outdoors types. Your average Joe wouldn't know a carabiner if it landed on his head.

But that's all changed. In a way, rock climbing has become like yoga, attracting people of all ages and backgrounds, with the important difference, of course, that you can't rock climb in your living room.

Outdoor climbing -- the most exhilarating version of the sport -- depends on a combination of good rock, good formations and legal access. If you're fairly new to the sport, it's also essential that there be plenty of easy climbs to build up your confidence.

Great Falls Park has all those things and more. Just 14 miles from Washington on the Potomac River, it's the most breathtaking climbing destination in the region.

Rapids surge through a narrow canyon called Mather Gorge as climbers cling to 50-foot-tall walls, all the while dangling over swirling waters. Needless to say, it sure beats spending a day at the office.

But while Great Falls has plenty to challenge the advanced climber, it also boasts lots of spots perfectly suited to the beginner. The Yosemite Decimal System assigns numerical values to rock climbs from 5.0 (the easiest) to 5.15 (the most difficult). Anything below a 5.7 is appropriate for most beginners, and Great Falls has almost 80 climbs in the 5.0 to 5.6 range.

Great Falls is essentially a top roping area. In top roping, a climber is harnessed to a climbing rope that passes up through two carabiners -- metal loops -- secured at the top of the climb and then back down to a trained climbing partner, who pulls up the slack as the climber ascends -- a technique called belaying.

Aside from good climbing, what makes Great Falls so spectacular is the falls itself. That's one reason Mark Kochte, a professional climber and the author of the book "Climb Maryland!" (Dog Days Graphics, 2003), has been hitting the rocks at Great Falls since 1988.

"Due to the proximity of the falls and the Potomac to the cliffs, Great Falls has a magical quality all its own you won't find anywhere else in the region," he says.

Phil Zook Friesen, who is in charge of the outdoor recreation program at Johns Hopkins University, says he takes novices to Great Falls all the time.

"We bring beginning Hopkins students there because there are easy routes and a great view. Beginners don't want to climb all day; we can take a break, eat lunch, take a hike. There are a lot of things to do that make it beginner-friendly." He adds that because the walls are only 50 feet high, Great Falls isn't intimidating to novice climbers.

But whether a climb is 50 feet or 300, it can still be dangerous. So first-timers would do well to bone up on their skills in advance at a professional climbing gym. There are Earth Treks Climbing Centers in Columbia and Timonium, Md., and a third will open this fall in Rockville (800-254-6287 or www.earthtreksclimbing.com). Another good bet is Sport Rock (www.sportrock.com), which has facilities in Rockville (301-762-5111), Alexandria (703-212-7625) and Sterling (571-434-7625). At a climbing gym you'll learn all the techniques and knots you need to safely set up a top rope and belay a climber. You'll also get a leg up on your climbing -- when you get to the falls you can jump right on a 5.6 and move up from there.

Dihedrals, Romeo's Ladder, Sandbox, Seclusion, Degree 101: These are some of the walls at Great Falls that have easy and challenging routes of varying Yosemite Decimal ratings. At Dihedrals, for instance, 16 routes are rated from 5.1 to 5.11, and one top rope rigging will give you access to routes such as Pride (5.4), Photo-Op Arete (5.7), Layback Dihedral (5.4) and Ender (5.11). Ender might be a little out of your league, but it's a kick to get on a really difficult climb just to get an idea of how much there is to learn.

Yet another advantage of Great Falls is the unique geographical features of the beginner climbs. Layback, for instance, features two rock faces that form a dihedral angle with a crack at the point where the two faces meet.

To do this climb, a climber has to perform a layback maneuver -- hence the name -- which involves putting both hands in the crack and leaning back while placing your feet on the opposing wall. It's relatively easy on a 5.4 route, but pretty tricky on a 5.11. The nice thing about Layback is the opportunity it gives you to practice difficult and useful moves.

Of course, to find these walls, you'll need a guidebook. The Potomac Appalachian Trail Club's "Climbers' Guide to the Great Falls of the Potomac" (Tate, 2001) and Eric J. Horst's "Rock Climbing: Virginia, West Virginia and Maryland" (Falcon, 2001) are both excellent climbing companions.

Each guide gives you concise directions on where to find climbable faces, detailed graphics and maps of specific routes, as well as up-to-date ratings that will direct you to beginner climbs.

If you get lost, just ask anyone carrying a backpack laden with carabiners and climbing ropes. Climbers are generally very friendly people, and most will be eager to give you a little beta -- climber-speak for information gathered from experience.

ROCK CLIMBING AT GREAT FALLS PARK -- 9200 Old Dominion Dr., McLean. Open daily except Dec. 25 from 7 a.m. until dark. Visitors center open daily from 10 to 4, with extended hours in spring and summer. Three-day pass, $3 per person or $5 per vehicle. Annual park passes, $20. 703-285-2965 or 703-285-2966 or www.nps.gov/gwmp/grfa.

From the District, take Interstate 495 west toward Silver Spring. Take Exit 44 for Route 193, Georgetown Pike. At the top of the ramp, turn right at the traffic light onto Route 193 west. After about three miles, there will be another traffic light at Route 193 and Old Dominion Drive. Turn right. Old Dominion Drive will dead end at the park entrance station, about one mile down the road.

Always check Potomac River water levels before going to Great Falls, especially in the spring. (This information can be obtained by calling the park.) When levels are high, the bases of many climbs are submerged, which can make them difficult for beginners. And don't ever swim or wade in the water. The current is strong, and drownings are not uncommon.

Chris Bullwinkle, 22, tackles the Layback Dihedral wall at Great Falls Park in Virginia. The climb is one of nearly 80 beginner-friendly challenges at the park, which features 50-foot-tall walls along the swirling Potomac River. Climber Bullwinkle gets assistance from Phil Zook Friesen, 32, in back, who runs the outdoor recreation program at Johns Hopkins University.