“The Empire Strikes Back” looks and feels real and lived-in because it was filmed in actual places, including George Lucas' swimming pool, which doubled for a swamp in Dagobah.

When Luke Skywalker first lands his X-Wing fighter on Dagobah, he gets it stuck in the swamp and his faithful astromech droid, R2-D2, falls into the water but quickly surfaces.

Right behind R2-D2 comes the fin of a fearsome dragonsnake, which swallows the droid before spitting it out. The “Star Wars” crew called the dragonsnake the “bog creature.”

The shot of the bog creature's fin in the scene was a pickup shot, meaning it was filmed to plug a gap in the flow of images after principal photography had wrapped.

Shooting at Lucas’ home was more convenient than returning to film in England, and the shot was a close-up, so they trucked in the bog creature and used Lucas' pool for

the insert.

Lucas lived on the coast of sunny California, which posed a lighting challenge for the crew as they were filming the pick-up shot of the bog creature.

Outfitting the pool with a diffuser screen solved the crew’s lighting issues for the shot, and a pair of scuba divers came in to operate the bog creature from underwater.