Medusa is the world's first floorless roller coaster, and it is found at Six Flags Great Adventure in New Jersey. It is a steel roller coaster that measures in at 142 feet tall, 3985 feet long. The tallest drop is 13 stories tall (132 feet). Medusa's top speed is 61 miles per hour, and the ride lasts 3 minutes and 15 seconds. Riders on Medusa will experience: 1 vertical loop, 1 dive loop, 1 zero-g roll, 1 cobra roll (2 inversions), and interlocking corkscrews.
Medusa was built by Bolliger & Mabillard (B & M), at a cost of $15,000,000, and was opened on April 4th, 1999.
Medusa has a lime green track with a purple support structure. There are 3 trains, each with 8 rows of 4 seats. Riders are strapped into a floorless chair on top of the track in the open-sided, floorless train. The wide space between each row adds to the floorless effect by allowing riders to view the track disappearing beneath them.
The ride is incredibly smooth, and is similar to that of a suspended coaster. The first hill packs a surprise at the top, and when banking around turns, the riders' legs fly out, accentuating the flying effect.
One of my personal favorites because of the smooth ride. Medusa is simply a superior roller coaster.
Sources: Roller Coaster Database (rcdb.com), Six Flags (sixflags.com), and personal experience.