Once upon a time, doing extreme outdoor sports meant traveling far away from city life. There were no vending machines. When night came, it got dark. The terrain was laid out without a floor plan. There was something called "weather," and the seasons determined what you did (that grass skiing thing never quite caught on). Now, for better or worse, those days are over. Humans have brought the outdoors inside, or they've simply recreated it outdoors, so your favorite adventure activity has an all-new, man-made, super convenient location.
Click through for nine of the wildest man-made environments.
Clear Creek White Water Park, Golden, Co.
Kayak parks have become more common in recent years, althought they aren't so much "man-made" as "man-improved." Clear Creek White Water Park, for example, was built right in the middle of Clear Creek in Golden, Co., by adding boulders and other elements to a quarter-of-a-mile stretch. Flows get pretty heavy -- and cold -- with the winter snowmelt. But if you like Class II rapids, you can find 800 feet of whitewater joy.
Wave House, San Diego, Calif.
Why sit around waiting for the surf when you can ride never-ending perfect curls at San Diego's Wave House? The park has two different wave machines: the FlowRider, which is a small wave for beginners, and the FlowBarrel, a tubing, 10-foot beast for serious devotees.
You can also find Wave House swells breaking in Durban, South Africa; Santiago, Chile; and Sentosa, Singapore.
Ski Dubai, Dubai, U.A.E.
Indoor ski areas have taken the globe by storm, from the massive slopes of SnowWorld in the Netherlands to the giant Art Deco tubeworm that is Moscow's Snej. But there's something particularly wild about shredding powder in the middle of the desert. We're still waiting to see if the indoor, glass-topped Dubai Sunny Mountain Ski Dome gets built, but in the meantime, visitors can head over to "Ski Dubai." The indoor resort -- part of the Mall of the Emirates -- is 242,188 square feet and includes a 197-foot-tall mountain with five different slopes. If skiing or boarding isn't your thing, the slopes are connected by a Snow Park play area with sled and toboggan runs, an ice cave, an ice slide and climbing towers. Whatever you choose to do, you can't complain about spending a day on the cool slopes when it's a sweltering 110 degrees outside.
Edinburgh International Climbing Arena, Ratho, Scotland
Indoor climbing walls began as a novel use of space,. Now they're being perfected as a science and an art form. In most cities these days, you can find at least one facility. But the mother of all indoor climbing walls is in Scotland. The Edinburgh International Climbing Arena, which was built in an old rock quarry, features 26,000 square feet of artificial walls and another 4,300 square feet of bouldering terrain.
Ecco Indoor Trail, Dortmund, Germany
What can't be done indoors? Nothing. Take the Ecco Indoor Trail, which was first constructed in February 2012 in Dortmund, Germany, for an all-terrain footrace. The three-quarters-of-a-mile-long trail featured slime pits, small forests, snowfields and rubble fields. Next February, organizers have plans to recreate a "mountain and a sand desert."
Ray's Indoor Mountain Bike Park, Cleveland, Ohio.
You'd think mountain biking was something that, by definition, would have to be done outdoors, but Ray Petro has proven otherwise. Petro started his first indoor mountain bike park in Cleveland as an escape from the town's snowy winters. The concept was so successful, he recently opened a second location in Milwaukee. Now similar parks are being built around the country in places like Portland, Ore., Boulder, Co., and Syracuse, N.Y. Who said you needed mountains to mountain bike?
Salomon Center, Ogden, Utah
At Utah's Salomon Center you can do away with gravity altogether, thanks to the iFly vertical wind tunnel located in this huge multi-sport complex. It's like sky diving without the plane, BASE jumping without the danger, or falling without the unpleasant landing. Sure, you can find these wind tunnels elsewhere, but the Salomon Center also features an indoor river for wakeboarding; surfing and body boarding; a climbing wall, a Gold's Gym and more.
U.S. National Whitewater Center, Charlotte, North Carolina
Whitewater rafting is fun, but it usually requires a long drive to reach a proper put-in. Wouldn't it be nice if a run were a little closer to town? That's what the creators of the U.S. National Whitewater Center in Charlotte thought when they opened this popular facility in 2006. The center offers a nearly mile-long loop featuring Class II-IV whitewater rapids -- all within the city limits. Of course, not all of the half-million visitors in 2011 were rafting. Some were paddle boarding, canyon crossing, ecotrekking, mountain biking, and even zip lining. But hey, in Charlotte, there's always time for one more run.
Next: 15 Gut-Wrenching Wipeout Photos
XC, Hemel Hempstead, U.K.
As part of the new $40 million "XC" (for "Extreme Challenge") extreme sports facility in Hemel Hempstead, designers included one of the largest indoor caving systems in the world. The sports center was designed to help promote activity among English youth. In addition to a skate park replete with quarter pipes and a bowl, XC includes 500 feet of life-like caves twisting through three chambers. One of them culminates at a nearly 40-foot-high ropes course.