Results: Would you ride the scariest thrill rides on the planet?

X2 Six Flags Magic Mountain Los Angeles(Valencia) First opened in 2002 as the world's first "fourth-dimensional" ride, with 360-degree rotating seats and headfirst, facedown drops, Six Flags Magic Mountain's X was closed in 2007 for a $10 million rejiggering. This May it has emerged, phoenixlike and more spine-tingling than ever, with new immersive tunnels, more audio and visual enhancements, and sleeker wing-shaped trains. For the uninitiated, it's called four dimensional, or 4-D, because the seats extend off the track to the sides, allowing riders to independently rotate head over heels, forward and backward—giving that mind-bending dimensional effect. Would you ride the X2?

Insanity Stratosphere Hotel and Casino Las Vegas. Not all the scariest rides are roller coasters, a fact that everyone who has been to the top of the Space Needle-like Stratosphere hotel in Vegas knows only too well. Perched over the Strip, the most frightening of the Stratosphere's three rides is an electric-green-colored centrifuge called Insanity, which extends 64 feet over the north edge of the tower. Spinning over 40 mph, riders are angled down by 70 degrees so all they see is the street, 900 feet below. This is truly one of the world's most harrowing rides. Would you ride Insanity?

Fahrenheit Hersheypark Hershey, Pennsylvania. Opened in May 2008, the so-called "sweetest place on earth" just got edgier. This inverted vertical loop "lift" coaster starts off swooping riders up 121 feet above the ground only to plunge them right back down in a gut-wrenching, 97-degree negative drop—the steepest in the U.S. At the 121-foot crest, the upcoming drop is at such a steep incline that the only thing riders in the stadium-seating trains see is, well, nothing. No track at all. Once you survive that first drop, there's still more to come: a 107-foot inverted loop, an inverted corkscrew roll, cobra element, airborne inverted S-roll, another inverted corkscrew, a little airtime hill (stomach floating), a high-speed banked curve, another hill, and then a high-speed banked curve to end it. All this action takes place in about 85 seconds—less time than it takes to polish off a Hershey bar. Would you ride Fahrenheit?