Question: Where is the location of formation of Sanctuary's performer?

full_context: Document 1: Sanctuary (Iron Maiden song): "Sanctuary" is the second single released by the British heavy metal band Iron Maiden. The single was released on 23 May 1980. Although originally issued as a non-album single, the song was added to the later US release of their debut studio record, "Iron Maiden" (1980). When the album was re-released in 1998, the song was added in all territories. In 1990, the 12" version was reissued on CD and 12" vinyl in "The First Ten Years" box set, in which it was combined with their first single, "Running Free".
Document 2: Beast over Hammersmith: Beast over Hammersmith is a live album by the British heavy metal band Iron Maiden, released on 4 November 2002. Recorded 20 years previously, during The Beast On The Road tour at the Hammersmith Odeon, the footage was specially co-produced and mixed by Steve Harris and Doug Hall to be a part of the Eddie's Archive box set. Even though this album contains material from "The Number of the Beast", it was actually recorded two days prior to its release (although "Run to the Hills" had already been released as a single).
Document 3: Fear of the Dark (Iron Maiden album): Fear of the Dark is the ninth studio album released by English heavy metal band Iron Maiden. Released on 11 May 1992, it was their third studio release to top the UK albums chart and the last to feature Bruce Dickinson as the group's lead vocalist until his return in 1999.
Document 4: Iron Maiden: Iron Maiden are an English heavy metal band formed in Leyton, East London, in 1975 by bassist and primary songwriter Steve Harris. The band's discography has grown to thirty-nine albums, including sixteen studio albums, twelve live albums, four EPs, and seven compilations.
Document 5: The Final Frontier: The Final Frontier is the fifteenth studio album by British heavy metal band Iron Maiden. It was released on 13 August 2010 in Germany, Austria and Finland, 17 August in North America, 18 August in Japan, and 16 August worldwide. At 76 minutes and 34 seconds, it is the band's second-longest studio album to date, a duration surpassed only by 2015's "The Book of Souls".
Document 6: Running Free: "Running Free" is the debut single by Iron Maiden, released on 8 February 1980 on the 7" 45 rpm vinyl record format. It was written by Steve Harris and Paul Di'Anno. The song appears as the third track on the band's debut album "Iron Maiden" (and the fourth track on its 1998 re-release). In 1985, a live version of the song was released as the first single from "Live After Death" (the band's twelfth single). In 1990, the original single was reissued on CD and 12" vinyl as part of "The First Ten Years" box, in which it was combined with the band's next single, "Sanctuary". The 1985 live single was also released as part of this box set, combined with 1985's "Run to the Hills".
Document 7: Twilight Zone (Iron Maiden song): "Twilight Zone" was the fourth single by Iron Maiden, released on 2 March 1981 and is the lead single to the 1981 LP "Killers". The song did not appear in the original album in February, but was included in the U.S. release in June and the international 1998 remaster. At the time of its release, it was the band's second-most successful single, peaking at No. 31 in the UK Singles Chart. It is the band's first single to feature guitarist Adrian Smith. In the 1990 box set, "The First Ten Years", it is on the same CD and 12" vinyl as the previous single, "Women in Uniform".
Document 8: Classic Albums: Iron Maiden – The Number of the Beast: Classic Albums: Iron Maiden -- The Number of the Beast is a documentary about the making of the album of the same name by the British heavy metal band Iron Maiden, released on 26 November 2001 as part of the Classic Albums documentary series. Directed by Tim Kirkby, it featured cuts from the title track, ``Children of the Damned '',`` Run to the Hills'', and ``The Prisoner, ''in addition to extended interviews and live footage of`` Hallowed Be Thy Name'', recorded during the band's performance at the Rock in Rio festival in 2001.
Document 9: List of Iron Maiden concert tours: Iron Maiden are a British heavy metal band, founded in 1975 by bassist Steve Harris in London, England. After several personnel changes in the 1970s, the band settled on a lineup of Harris, Paul Di'Anno (lead vocals), Dave Murray (lead and rhythm guitars), Dennis Stratton (backing vocals, lead and rhythm guitar) and Clive Burr (drums), before they set out on their first professional tour, the Metal for Muthas Tour which supported the compilation album of the same name. After taking on a supporting slot with Judas Priest on their British Steel Tour and setting out on their own headline tour in support of their debut album, "Iron Maiden", the band supported Kiss on the European leg of their Unmasked Tour, following which Stratton was dismissed because of musical differences. Guitarist Adrian Smith was hired, following which Iron Maiden set out on a short series of UK dates before recording their second studio album, "Killers".
Document 10: The Number of the Beast (song): ``The Number of the Beast ''is a song by the English heavy metal band Iron Maiden. It is Iron Maiden's seventh single release, and the second single from their 1982 studio album of the same name. It was reissued in 2005 and also prior to that in 1990 in The First Ten Years box set on CD and 12'' vinyl, in which it was combined the previous single,`` Run to the Hills ''.
Document 11: Iron Maiden (album): Iron Maiden Studio album by Iron Maiden Released 14 April 1980 Recorded January 1980 Studio Kingsway Studios, London, England Genre Heavy metal Length 37: 35 Label EMI Harvest / Capitol (North America) Producer Wil Malone Iron Maiden studio albums chronology Iron Maiden (1980) Killers (1981) Killers 1981 1998 remastered version cover Singles from Iron Maiden ``Running Free ''Released: 8 February 1980`` Sanctuary *'' Released: 23 May 1980 * Not an original album track, but added to later editions
Document 12: Maiden Japan: Maiden Japan, also known as "Heavy Metal Army", is a live EP by the British heavy metal band Iron Maiden. The title is a pun of Deep Purple's live album "Made in Japan".
Document 13: Iron Man (song): ``Iron Man ''is a song by British rock band Black Sabbath. It is taken from their second studio album, Paranoid, released in 1970. It was later included on their initial greatest hits compilation We Sold Our Soul for Rock 'n' Roll (1976), as well as all subsequent greatest hits compilations; The single version was included on the Greatest Hits 1970 -- 1978 album.
Document 14: British Lion (album): British Lion is the debut solo album from Steve Harris, best known as the bassist and primary songwriter for the British heavy metal band Iron Maiden. The album was announced on 18 July 2012 and released on 24 September.
Document 15: The Number of the Beast (song): "The Number of the Beast" is a song by the English heavy metal band Iron Maiden. It is Iron Maiden's seventh single release, and the second single from their 1982 studio album of the same name. It was reissued in 2005 and also prior to that in 1990 in "The First Ten Years" box set on CD and 12" vinyl, in which it was combined with the previous single, "Run to the Hills".
ground_truth: Leyton
sub_queries: Sanctuary >> performer Answer: Iron Maiden
Iron Maiden >> location of formation Answer: Leyton