The happiest place on Earth? Inside Walt Disney's luxury estate with underground RAILROAD that inspired him to build Disneyland

Walt Disney's personal pride and joy, the estate he last called home and the property which was the inspiration for Disneyland - has gone on salefor a whopping $90million. The Carolwood Estate is considered the birthplace of the1955 theme parkand is the place where Disney imagined the vast expansion of his animation company into amusement parks. In 1950 the mogul builta one-eighth-scale backyard steam train around the estate's grounds - it is still evident at the Los Angeles property today with a tiny doorway into one of its underground tunnels. It was enjoyment of his personal train line that convinced Disney to develop rides and an amusement park fans could visit. Disney and his wife Lillian saidthe property onCarolwood Drive, in Holmby Hills, was their 'dream home' and it soonbecame known as the Old Disney Estate. A steam enthusiast, Walt Disney, soon got carried awaywith his pet project on the grounds, developing a huge control room in a barn as he expanded the train's route, twists and turns until it became known as the Carolwood Pacific Railroad.