What year was the September 11 Memorial constructed?
2006
2002
2002
2002
2002
2001
2002
2001
2002
2001
2002
2001
2002
2001
2002
2001
2002
2001
2002
2001
2002
2001
2002
2001
2002
2001
2002
2011
2001
2002
2011
2001
2002
2011
2001
2002
2011
2001
2002
2011
2001
2002
1912
2011
2001
1912
2011
2001
2009
2011
2001
1912
2009
2011
2001
1912
2009
2004
2011
1913
2009
2004
1912
2011
2000
2012
2009
1913
2004
2011
1912
2000
2012
2009
2004
2011
1913
2000
1912
2012
2009
2004
2011
1921
2000
1913
2012
2009
2004
1912
2011
1921
2000
2012
2009
1913
2004
2011
1922
1912
2000
1909
2012
1921
2009
2004
2011
1913
2000
1922
1912
2003
2005
2012
2009
2006
2004
2011
1909
1921
2000
1913
2003
2005
2012
2009
1922
2006
2004
1912
2011
2014
1909
1921
2000
2003
2005
2012
2009
1913
2006
2004
2011
1915
1922
1912
2014
2000
1903
2003
1909
2005
2012
1921
2009
1931
2006
2004
1913
2014
2000
1915
2007
1922
1907
1912
2003
2016
2005
2012
2009
1903
2006
2004
1909
1921
1999
1931
2014
2000
1902
1913
2007
2017
2003
2016
2005
2012
2009
1915
1922
1907
2006
2004
1912
1999
1903
2014
1909
1921
2000