The design of the building neo-gothic, which is European (specifically popular in Britain, look at the Parliment building). Wealthy famlies in the US patterned their mansions after European architecture. Think of Toad Hall . . . another neo-gothic building in DL and DLP.Actually the Haunted Mansion is not European. It's design idea was mansions in the Hudson River Valley in New York, and an actual mansion in Pennsylvania was used by artists to sketch some details.