Finding Nemo Submarine Voyage
The submarine voyage has been a staple of Tomorrowland at Disneyland since it opened, being the only long term successful ride to ever fill the lagoon. When it closed it left a giant hole (Literally) in the park.
Luckily Disney saw fit to bring this ride back. They just had to wait for the right movie. They wanted to with Atlantis, but it flopped. Then came Finding Nemo.
It was an almost perfect situation. Disney had a new popular movie and Disneyland had a usable underwater ride system.
This was a hit since it opened, despite problems with claustrophobia and being slow loading. It transports you into the Great Barrier Reef along with Nemo and his friend by bringing you under water to his world.