Join us on Expedition.. Expedition Everest: Legend of the Forbidden Mountain as we look through the history of Walt Disney World's most expensive roller coaster ever. Now 15 years old, this Vekoma roller coaster at Animal Kingdom turned the theme park into more than just a zoo. As one of the best rides anywhere in the world, it only had one large problem. The Yeti would break shortly after opening and be put into a mode of Disco.