The towers came crashing down in the terrorist attacks on America in 2001, but a memorial at Ground Zero has been created to honour the dead.

A week after the Pope visited the water pools that stand where the Twin Towers did, Gordon-Levitt reveals he had a very spiritual moment there as he attempted to visualise Petit's wire walk between the two buildings in 1974.

The actor tells WENN, "For this film, I stood in between the two pools which are the footprints of the old towers and walked from the north corridor of the South tower to the south corridor of the North tower, like Philippe, just to see what it was like - and it's a long walk!"