Oooooh, aaaaaah! Watch the Lagoon of Nations in action! Clip 1 (4.6B) Clip 2 (3.7MB)
The Lagoon of Nations was later refurbished as The Fountain of the Planets for the 1964-65 World's Fair. In both cases the water, lights and fireworks were "choreographed" to music. The 64-65 version used pre-recorded music, but in 39-40 the music was performed live!