Date: Saturday November 1, 1930
Location: Manhattan, New York, United States of America

The Daleks do not utter the phrase "exterminate" or fire their energy weapons in this episode.

This is the first episode of the series in which Rose Tyler (Billie Piper) is neither seen nor mentioned.

Filming locations: Parc and Dare Hall, Treorchy, South Wales (the dance hall), New York City, New York (background plates only). The latter represents the first time the new series has done overseas filming.

The Doctor: We've been to New New York. Well, there's the genuine article. So good they named it twice. Mind you, it was New Amsterdam originally. Harder to say twice, no wonder it didn't catch on. New Amsterdam, New Amsterdam.

Tallulah: (to Martha) It's the Depression, sweetie. Your heart might break but the show goes on cos if you stop, you starve.

Martha: This is insane, it's inhuman!
Dalek Thay: We are not human!

The Doctor: (referring to the Daleks) They always survive while I lose everything...

Dalek Sec Hybrid: I...am...a human...Dalek...I...am your future!

The Statue of Liberty is shown with a gold-plated torch. In reality, this was not added until the 1980s renovation, more than fifty years after the events of this episode.

This episode reveals that Skaro, like Gallifrey, was destroyed in the Time War.

The Doctor (in his first incarnation) and the Daleks previously visited the Empire State Building in the original series second season episode "The Chase." That makes the Daleks' plan a potential paradox, since they are interfering in their own timeline (creating a series of events that would make previous actions paradoxically impossible to happen), but the vagaries of time travel mean it's not clear whether that's the case.

The Daleks state Skaro was destroyed during the Time War. However, Skaro was previously shown to be destroyed by the 7th Doctor during "Remembrance of the Daleks." However, Russell Davies has stated that some of the events seen in the original series were opening salvos in the Time War, which by definition isn't limited to a straight past-present-future series of strikes and counter-strikes.