Finding Nemo Submarine Voyage is a boat ride in Tomorrowland at Disneyland. It's worth seeing on a time-permitting basis.
The submarine ride uses Disneyland's largest show building, as all elements needed to be duplicated so that both sides of the submarine could see the same thing. Thanks to "sonar hydrophones" you can hear Nemo and friends talk as you ride underwater past reefs, through caverns and into the East Australian Current. The 15-minute ride also includes encounters with Bruce and the sharks, deep-sea anglerfish, whales, and an underwater volcano.