Combining speed, height, and a totally flimsy harness that in no way looks like it can hold you up, ziplining is sheer excitement meets pure terror -- an exhilarating ride atop some of the planet's most gorgeous landscapes. But which lines are worth the zip? From 165ft underground to 1,000ft in the air, here are six of the world's longest, fastest, and wildest.
The Beast -- Orocovis, Puerto Rico
Top Speed: 65mph
Scare Factor: Suspended 1,000ft in the air, this zipline's been named the highest in the world. Upon reaching the platform, you'll strap yourself in face down, "Superman Style"; from there, you can soak in the view of the rainforest, rivers, and valleys below as you fly down the mountain in a two-minute, adrenaline-filled rush.
SkyRider -- Hunter Mountain, NY
Top Speed: 50mph
Scare Factor: Why head to a tropical locale when you can zipline year round in the scenic, not-at-all-congested-in-the-Winter, Catskill Mountains? Soaring nearly 600ft above the ground, SkyRider's the longest and highest canopy tour in North America and features five separate lines with side-by-side racing zips, so you can compete with friends.
Mega Zips at Mega Cavern -- Louisville, Kentucky
Top Speed: 35mph
Scare Factor: Looking to up the ante when it comes to thrills and shrills? Then head 165ft below the Earth's surface to the only zipline on the planet that's totally underground. Suspended 70ft in the air, the ride features six lines in a cavern that boasts 17 miles of passageways, all of which are beneath one of the most hipster cities in America, Louisville. End your tour by racing friends on the dual line.
Zip2000 -- Sun City, South Africa
Top Speed: 115mph
Scare Factor: With average speeds hitting 75mph, this line's the fastest and probably most terrifying in the world. As you hurl yourself towards the earth, you'll even have to place a fin between your legs to ensure you stay on line. Available solo or in tandem, this straight shot is done lying on your stomach to get the full flying effect.
Miss Sky Canopy Tour -- Nosara, Costa Rica
Top Speed: 28mph
Scare Factor: With two excursions offered, most people stick with the North tour; it's dubbed the world's longest zip and features 21 separate runs -- on that tour, plan on riding through waterfalls and from mountaintop to mountaintop across the jungles of Costa Rica. If you're more of an adrenaline junkie, try the South tour, which clocks speeds at almost 40mph.
AdrenaLUNA -- St. Lucia
Top Speed: 25mph
Scare Factor: Open only three days a month around the full moon, St. Lucia's AdrenaLUNA takes place in the middle of the night. More than just a quick thrill ride, though, this adventure requires trekking through the rainforest, walking over some floating steps, swinging from Tarzan's rope, and rappelling back to the base camp -- all with nothing but a few spotlights and a lamp strapped to your head.