Walt Disney made up Disneyland as he went along during construction in the mid-1950s

Walt Disney made up plans for Disneyland as he went along during the yearlong construction blitz in the mid-1950s that his critics mocked as impossible and predicted would become a spectacular failure, according to a new documentary about the making of the Anaheim theme park.

Disneyland Construction Supervisor Joe Fowler said work began in July 1954 with virtually no plans for the park in the new “Disneyland Handcrafted” documentary by filmmaker Leslie Iwerks that debuted Thursday, Jan.