Question: In what city did Amir Khan and Lamont Peterson fight for the welterweight titles in 2011?

Context articles: Andre Berto vs. Victor Ortiz
Amir Khan vs. Marcos Maidana
Amir Khan II
Lamont Peterson
Amir Khan vs. Zab Judah
Ryan Barrett
Amir Khan vs. Paul McCloskey
Amir Khan III
Amir Khan vs. Lamont Peterson
Amir Khan (boxer)

Andre Berto vs. Victor Ortiz was a welterweight world title fight that aired on HBO's "Boxing After Dark" on April 16, 2011.
 As part of an HBO televised broadcast, the split-site double-header included WBA junior welterweight Championship Amir Khan vs. Paul McCloskey, Khan fighting from his native England.
Light welterweight titlist Amir Khan and interim titlist Marcos Maidana reached an agreement to meet on December 11, 2010.
 The bout was for Khan's WBA Light Welterweight Title, which Khan successfully defended, winning via unanimous decision.
 The fight was awarded Fight of the Year by the Boxing Writers Association of America.
Amir Khan II surnamed Mir Miran the son of Khalilullah Khan Yezdi was a nobleman of high rank in the time of the Mughal emperors Shah Jahan and Alamgir and a great favorite of the latter.
 He was Subedar or governor of Kabul.
 He died at Kabul on the April 28, 1698 and the emperor conferred the title of Amir Khan III on his son.
Lamont Peterson (born January 24, 1984) is an American professional boxer.
 He is a two-weight world champion, having held the WBA (Regular) welterweight title since February 2017.
 Previously he won the WBA (Super) and IBF light welterweight titles in 2011 by controversially defeating Amir Khan, but was later stripped of both titles; the WBA in 2012 for failing a drugs test, and the IBF in 2015 for his non-title loss to Danny García.
 Peterson also held the WBO interim light welterweight title in 2009.
WBA titlist Amir Khan and IBF titlist Zab Judah reached an agreement to meet for a unification bout for the IBF and WBA Light Welterweight Titles, on July 23, 2011 at the Mandalay Bay Resort & Casino, Las Vegas, Nevada.
Ryan Barrett (born 27 December 1982) is an English boxer.
 He is the current WBU Welterweight World Champion and former English Super Featherweight Champion and British Masters Featherweight champion.
 Barrett is best known for his loss to 2004 Athens Olympics silver medalist Amir Khan via a TKO; since this fight, he has gone on to fight for both British titles and world titles.
Amir Khan vs. Paul McCloskey was a 140-pound world title fight, that was aired on HBO's "Boxing After Dark", as part of an HBO-televised split-site double-header, which also included WBC Welterweight Championship fight, Andre Berto vs. Victor Ortiz.
 Following on from Khan's successful title defense against Marcos Maidana, Champion Amir returned to Manchester to continue his title defense against EBU Super Lightweight Champion Paul McCloskey at the Manchester Evening News Arena.
Amir Khan III was the title of Muhammad Ishaq the son of Amir Khan II and a descendant of the celebrated Shah Na’matullah Wali.
 He was a favorite of the Emperor Muhammad Shah but was appointed governor of Allahabad in 1739 against his wishes due to the Vizier Qamar ud-Din Khan and re-called to court in 1743 C.E.
 He was naturally of free speech and the emperor fond of his repartee had him more license in his conversation than was consistent with respect to his own dignity when he was on business with the emperor which by degrees disgusted Muhammad Shah and made him wish his removal from office.
 He was consequently with the consent of the emperor stabbed with a dagger by a person who had been discharged from his service and fell down dead on the spot.
 This circumstance took place on Friday the December 26, 1747.
 He was buried after four days in the mausoleum of Khalilullah Khan his grandfather which is close to the Sarai Ruhullah Khan at Delhi.
 His poetical name was "Anjaam".
 He composed logo-graphs and has left Persian and Rekhta poems.
 There is a full account of Amir Khan in the "Sujar ul Mutukharin" where he is said to have died in the same year as the emperor.
Amir Khan vs Lamont Peterson, billed as Capital Showdown, was a boxing match for Khan's WBA (Super) & IBF light welterweight titles.
 The fight took place in the Convention Center in Washington, D.C., United States, on 10 December 2011.
 Khan was making the first defense of his IBF belt against his mandatory challenger.
Amir Iqbal Khan (born 8 December 1986) is a British professional boxer.
 He is a former unified light-welterweight world champion, having held the WBA (later Super) title from 2009 to 2012, and the IBF title in 2011.
 Additionally he held the Commonwealth lightweight title from 2007 to 2008, the WBC Silver welterweight title from 2014 to 2016, and has challenged once for a middleweight world title in 2016.