Space Mountain.
"In what was the greatest spectacular event Central Florida has seen since the Grand Opening of Walt Disney World, Tomorrowland was dedicated and Space Mountain officially opened in a colorful extravaganza Wednesday afternoon. Just moments after Mickey Mouse took a bow and said, 'Ladies and Gentlemen, we proudly present... Space Mountain,' hundreds of red, white and blue fireworks exploded in the sky over Tomorrowland with 50,000 balloons soaring upwards to the tune of a 2,000 piece marching band..."
Robert Sarnoff, Chairman of the Board of RCA, and Donn Tatum, Chairman of the Board of Walt Disney Productions, unveiled the dedication plaque for Space Mountain. Along with the official opening of Space Mountain was the official opening of the Carousel of Progress and the Star Jets.
Space Mountain was the first computer-controlled thrill ride. In addition, the side-by-side tracks had one of the first computer-aided designs. Space Mountain actually originated in the early 1960s when Walt Disney conceived the idea of a high-speed thrill attraction based on the excitement of the Space Age.
Did you know that Space Mountain is more than 180 feet high, 300 feet in diameter and took more than two years to build? RCA was the first official sponsor of Space Mountain from 1975 until 1993, at which time Federal Express became the official sponsor. During the 2.5-minute ride your space rocket travels up to 28 miles per hour!
Did you know Space Mountain was "flight-tested" by U.S. astronauts and Russian cosmonauts? (taken from AllEars.net)