"Flesh and Stone" takes a classic Doctor Who idea—the Doctor and a diminishing number of associates are trapped on a spaceship and being hunted down—and twists everything. The spaceship is on the ground, there's a forest inside, and in the end, the aliens who are attacking are themselves attacked, but not by a foe any one of them can fight.

It's also memorable as being the story in which the Weeping Angels, who famously are never seen moving, turn their heads, move their arms and even talk. That they do so while remaining utterly creepy is one of the story's great successes.

(The episode is available on iTunes and Amazon.)

When discussing the art of writing Doctor Who with BBC Radio 4's Front Row, Steven Moffat revealed that the title was his son's idea: "They're always coming up with ideas for monsters, and the title for episode 5, 'Flesh and Stone' was Joshua's idea. I'd called it something to do with Angels, and he said 'we know there are angels, that's boring!'"

The idea of the crack in the wall—that became a crack in time—came from a similar mark on the wall of Steven Moffat's son's bed. Apparently it resembled a smile.

The scenes within the forest vault of the Byzantium were shot in Puzzlewood, an ancient woodland in the Forest of Dean. In an unrelated, but fascinating moment of three-way fandom crossover, Puzzlewood was also the location for a lot of Merlin, and it is thought to be one of J. R. R. Tolkien's inspirations for Middle-earth in The Lord of the Rings.

When the Doctor is discussing the forest, he says, "A forest sucking in starlight, breathing out air. It even rains." That latter sentence was added when filming in Puzzlewood was beset by heavy rain, which forced the camera crew to reschedule while filming.

Stephen Martin-Walters, who played Cleric Crispin, was unable to finish the shoot within the new schedule, so Cleric Crispin's scenes were hastily redrafted, with his lines being handed out to Marco, Pedro and Phillip.

https://www.youtube.com/watch?v=fIGCYqzjgRc

The Doctor has a habit of kissing his companions on the head just before he leaves them alone and nervous, while he goes to attend to other matters. The Second Doctor gave Zoe Heriot a reassuring kiss on the head "The War Games" and the Third Doctor did likewise to Jo Grant in "Colony in Space."

Amy isn't the only companion to have had to forgo her sight. Sarah Jane Smith believed she had been permanently blinded by Maren in "The Brain of Morbious," and Leela also believed her eyes to have been damaged by a flash of light from an exploding Rutan ship in "The Horror of Fang Rock." In that instance the flash actually changed the color of her eyes from brown to blue. This was a factor of the story that was written for production reasons, because Louise Jamieson, the actress who played Leela, had had to wear red contact lenses to make her eyes look brown for the part, but found that this made it very hard to see. After the Rutan ship blew up, Leela had blue eyes.

Director Adam Smith wanted Amy Pond's bedroom to be decorated in shades of blue to subtly highlight the impact the Doctor and the TARDIS had had on her.

While Steven Moffat wrote the "base code of the universe" scene with the intention that this would coincide with the date of broadcast for the final story in Season 5 ("The Big Bang"), the scenes were filmed before a final transmission schedule could be agreed. So several different versions of the date had to be filmed, all shown in U.K. date format order, as in 26/06/2010. The episode was first broadcast on different dates worldwide.

And of course, keep your eye on the Doctor when he, River and Octavian leave Amy with the other clerics. He pops back to check she's OK and remind her to think about what he told her when he was a child. Fans of production mistakes might leap on the fact that he's wearing his jacket (which the Angels ripped off him) and a different colored watch, however this the Doctor from "The Big Bang" popping back in time to help Amy remember him. All of that is done on purpose.

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