CAST:The Doctor - David Tennant
RATINGS:Overnight: 6.3 million
DID YOU KNOW?:
Construction of the Empire State Building began on March 17, 1930. Remarkably, it was officially opened just over a year later, on May 1 1931. 3,400 workers were involved in the project, of which five died during the construction. For 41 years, it stood proud as the tallest skyscraper in the world.
During the Great Depression, "Hoovervilles" housing the destitute and desperate appeared all over the United States. They were named after the 31st President of the United States, Herbert Hoover.
The Great Depression was an economic low point for the world, which started after the Black Tuesday stock market crash on October 29, 1929. Beginning in the United States, it quickly spread to the rest of the world, with devastating effects. International trade fell rapidly, as did personal incomes, tax revenues, prices and profits.
The Hooverville scenes were filmed in Cardiff's Bute Park.
Among the classic horror films and novels that helped inspire this story are The Island of Doctor Moreau, Frankenstein and The Phantom of the Opera.
This episode marks the first Doctor Who that has ever been filmed partially in the USA, albeit for effects shots and without any of the principal cast. The scenes on the rooftops and those in Central Park were filmed in Cardiff.
Tallulah's name and character were inspired by Jodie Foster's performance as Tallulah in the 1976 film Bugsy Malone.
Both the Daleks and the Doctor briefly visited the completed Empire State Building in The Chase; neither stayed long enough to appreciate any Dalek architecture that may have survived.
The Pig Men are the latest race of humanoid slaves used by the Daleks. Others have included Robomen (The Dalek Invasion of Earth), Ogrons (Day of the Daleks) and, er, humans (Resurrection of the Daleks)
The last time that the Doctor visited the USA, he was with Rose. On that occasion, he encountered what he believed to be the very last Dalek.
Sec is the first Dalek ever to wear shoes.
Fact File compiled by Peter Ware.