Next year marks the 75th anniversary of the release of one of the most popular movies in history. And Hollywood has begun  the lead-up to the celebration with a limited theatrical run of the Wizard of Oz that has been reconfigured in 3D and IMAX.

Technical experts say the conversion to 3D was made easier by the way the film was originally shot. Many of the special effects were created by combining different layers of film into one final print. They were able to use those layers to enhance the 3D experience.

They also used modern technology to make the Munchkins look smaller.

The Wizard of Oz is the oldest film to be restored in 3D. Early reports give it good reviews, saying it brings out many details missed in earlier prints. The 3D version will be in theatres for a week before a new DVD goes on sale.