story was partially filmed in the United States, a first for the programme. This production was done in Utah in November 2010. The story was co-produced by BBC America, who provided extra money for filming in the States. "The Rebel Flesh" and "The Almost People" was filmed in late November 2010 to January 2011, with much location shooting at Caerphilly Castle. "The Curse of the Black Spot" was filmed in Cornwall as well as the Upper Boat Studios, while some of "A Good Man Goes to War" was filmed in a hangar in Cardiff and began shooting mid-January 2011. "The God Complex" was mostly filmed on constructed hotel sets, and the low-budget "The Girl Who Waited" was intentionally set in "big white boxes". "Closing Time" was filmed at night in a department store, as well as a private home in Cardiff, with some filming reports in March 2011. "Let's Kill Hitler" featured Swansea and Cardiff's Temple of Peace as locations in Berlin. Filming concluded on 29 April 2011 with "The Wedding of River Song", though a scene from "Let's Kill Hitler" was delayed and filmed on 11 July 2011. Production blocks were arranged as follows: Release Promotion The first trailer for the sixth series was shown directly after "A Christmas Carol". In December 2010, BBC America began airing promotions for the new series with Smith and Gillan in character, announcing that they have landed in America. A 15-second teaser trailer was shown on BBC One at 9pm, 22 March 2011. This was followed by a one-minute trailer on 30 March 2011. BBC America followed with a one-minute trailer on 1 April. In addition, two radio trailers were broadcast in the UK in April. On 10 June 2011, the BBC released a short 30-second teaser trailer for the second half of the series. Smith and Gillan, alongside executive producers Piers Wenger and Beth Willis and "The God Complex" writer Toby Whithouse, attended the 2011 San Diego Comic-Con International in late June to promote the second half of the series. There a one-minute trailer and a clip of "The God Complex" was shown. A 40-second trailer was released on 4 August 2011 for BBC One. A 30-second trailer from BBC America was released on 12 August 2011. An alternative trailer aired on CBBC in August 2011. In addition, the BBC released prequels on the Doctor Who official website to promote some of