The man who made it possible for Julie Andrews to dance with penguins in Mary Poppins  and for James Cameron to create the planet Pandora in Avatar  has died.

Petro Vlahos was a two-time Academy Award winner who perfected the “green-screen” technique that allowed actors to be seen in any background.

The technique he perfected is known as “composite photography.”

Visual effects expert Bill Taylor says, “Whenever you see Mary Poppins dancing with penguins, when you see Pi in a boat in the middle of the ocean,  you are seeing Vlahos’ genius at work.”

Petro Vlahos also made it possible for Charlton Heston to survive the chariot race in Ben Hur.

He was 96.