"Toto... I've a feeling we're not in Kansas anymore..."
Since Judy Garland's Dorothy landed in Oz 75 years ago, the story has become as famous as the lines so often quoted. The arrival of the Wicked Witch of the West in a swirl of green smoke has entered cinematic history - and our collective consciousness.
With her pointed black hat and broomstick, a villain so vile, her image is resurrected by trick-or-treaters every year. She is the witch that made it mandatory to paint yourself green at Hallowe'en.
But have you ever wondered what turned her so evil? Or whether the Good Witch is really as perfect as she seems? That's the story in Wicked, the hit Broadway and West End musical that's arrived in Milton Keynes as part of a UK tour.
The action begins long before Dorothy crash-lands in Munchkinland. Elphaba and Glinda are students who become unlikely friends and begin a journey that turns them into powerful witches.
Preparing for an evening performance at Milton Keynes Theatre, Emily Tierney who plays Glinda the Good, explained: "We take these iconic witches that everybody knows from the Wizard of Oz and we show why one became wicked and why one was perceived to be good. We see them from their childhood right through to growing up and how misunderstood they both were."
Anthony Field, the company manager of the Wicked UK tour, takes me on a backstage tour. He has already revealed that many of the props have been hidden from our sight. The Wicked cast don't want to spoil the plot or shatter the illusion of magic. So Anthony refuses to reveal how they make the Wicked Witch of the West fly on her broomstick.
I am, however, invited to take a ride in Glinda's flying bubble. I'm clipped into a hidden harness then taken up for a panoramic view of the theatre and a closer look at tangle of metal and wires that control the sights and sounds of every performance.
We take a stroll through "Wardrobe Village" where hundreds of costumes, wigs and hats line cases on the walls.
"We have 31 members of the cast and with such quick changes it's important that they are close to the action so we're just about five feet behind the back of the stage," he explained. "This dress, which is worn by Elphaba, has very intricate detail and took around two to three months to make." It's made of 40 yards of different fabric. Glinda's bubble dress has 100,000 sequins and I'm surprised to discover that there's a member of staff employed just to sew on the ones that get knocked off during every performance.
The figures really are as impressive as the costumes. There are 319 pairs of shoes. 2000 metres of ribbon.
In the eerie darkness there's one case that catches my eye. It contains masks that turn the actors into animals - a talking goat and a legion of flying monkeys. Each one is moulded from prosthetic material to fit each actor's head perfectly.
But Elphaba's nightly transformation is much more time-consuming.
I catch up with actress Nikki Davis-Jones in her dressing room as she begins the 30 minute ritual. "It takes a lot of green make-up," she says. "It's nice to transform into the character, to finish getting ready for the performance and to get into character." So when the show's over, how does Nikki get the paint off again? "With great difficulty. The actresses start to get a permanent green tinge after a while."
Wicked is at Milton Keynes Theatre until March 8th.