The whole score starts off with outer space at the start of the bassoon solo. We see the Milky Way coming out of the darkness. Comets, the sun, and shooting stars whiz by. We come down to a planet which is Earth being born. Light from the volcanoes light up and the volcanoes burst with lava. Then the volcanoes explode. Lava pours down from a volcano with rocks and hits the water, creating a storm and the sea to rise up, flooding the volcano and everything around. Then everything went silent.
The scene changes to the sea when we see green and blue microscopic blobs that split up. We see many sea creatures. One of the fish went up to land and became the first amphibian to crawl on land. Later, the dinosaurs appear, living their lives of what dinosaurs do. Up on top of a cliff, Pteranodons swoop down to catch fish. One of them caught a fish but is pulled down by a Tylosaurus.
Everything was going so quiet for the dinosaurs. Every dinosaur is doing what the dinosaurs would do. Until then, they look up ahead, as rain begins to fall, and see the Tyrannosaurus Rex. He chases the dinosaurs and bites the Stegosaurus' tail. The Stegosaurus and the T-Rex both fight, with the T-Rex biting the Stegosaurus' neck and the Stegosaurus using his tail to beat the T-Rex. The dinosaurs look on while Stegosaurus does his last two hits and T-Rex bites his neck and brings him down, killing him. The dinosaurs leave while T-Rex eats his remains.
Later, everything was destroyed. There was no food and water for the dinosaurs, nothing but dried up pools, branches, ruined trees, and mud. The sun is too hot for them. The dinosaurs move on and some of them are stuck in the mud with Ceratosaurus coming to them. The wind blows and some dinosaurs collapse, including the T-Rex. Later, footprints are seen and we see the bones of the dinosaurs, showing that they are now extinct.
Just as the moon began to form an eclipse with the sun, an earthquake suddenly erupted, wiping the dinosaur bones away. The wind then blew a storm and the sea inland, the lowland and everything around became completely flooded, and everything was silent once again. At the end, when the eclipse was complete, you see it set over the only piece of land, overlooking a now endless sea. The film then goes to the intermission, which has the only appearance of the Fantasia title card.
List of animals that appeared
- A narrated version of the segment, titled "A World is Born", was produced as a school educational filmstrip in 1955. This version was a mainstay in science classes of the 50s and 60s and would inspire paleontologists such as Stephen Jay Gould to pursue it as a profession.
- Musical Score: Igor Stravinsky – Le Sacre du printemps
- Directed by Bill Roberts and Paul Satterfield
- Story Development/Research: William Martin, Leo Thiele, Robert Sterner, and John Fraser McLeish
- Art Direction: McLaren Stewart, Dick Kelsey, and John Hubley
- Background Paintings: Ed Starr, Brice Mack, and Edward Levitt
- Animation Supervision: Wolfgang Reitherman and Joshua Meador
- Animation: Philip Duncan, John McManus, Paul Busch, Art Palmer, Don Tobin, Edwin Aardal, and Paul B. Kossoff
- Special Camera Effects: Gail Papineau and Leonard Pickley