(CNN)Here's a look at the 9/11 Commission, whose report was released on July 22, 2004.
The Commission was created to provide a "complete account of the circumstances surrounding the September 11, 2001 terrorist attacks."
The official name of the 9/11 Commission is the National Commission on Terrorist Attacks Upon the United States.
The 570-page, 14-chapter report concluded that a "failure of imagination" kept U.S. officials from understanding the al Qaeda threat before the attacks on New York and Washington.
The report included 41 recommendations for reforming U.S. security agencies to fight terrorism.
The report called for a single national intelligence chief and a single counterterrorism center modeled on the military's unified commands. It also proposed the creation of a single, joint congressional committee to oversee homeland security.
The purpose of the commission was to investigate U.S. counterterrorism policy from August 1998 to September 11, 2001.
Budget for the Commission totaled $15 million.
It originally had 18 months to report, or no later than May 27, 2004, but Congress and the President extended the reporting deadline by two months, to July 26, 2004.
The Commission had nearly 80 full-time employees, contractors and employees on staff.
The Commission said it had access to all documents and interviews it requested.
"We've gotten everything we've asked for, but always after a lot of resistance and criticism," said member Slade Gorton.
It issued three subpoenas for information, but these were resolved without litigation. The subpoenas went to the Federal Aviation Administration (FAA), the Department of Defense and the City of New York.
The Commission reviewed more than two million pages of documents.
The Commission's 10 Members:
Thomas H. Kean, Chair - former governor of New Jersey (1982-1990)
Lee H. Hamilton, Vice Chair - former Congressman
Richard Ben-Veniste - Lawyer and former chief of the Watergate Task Force of the Watergate Special Prosecutor's Office
Fred F. Fielding - Has served on several commissions, including Commission on Federal Ethics Law Reform (1989)
Jamie S. Gorelick - Serves on the CIA's National Security Advisory Panel
Slade Gorton - Senator from Washington State from 1981-1987 and 1989-2001
Bob Kerrey - Senator for Nebraska from 1988-2000 and Nebraska Governor from 1983-1987
John F. Lehman - Chairman of J.F. Lehman & Company, a private equity investment firm and former Secretary of the Navy from 1981-1987.
Timothy J. Roemer - President of the Center for National Policy and Representative to Congress from Indiana 1991-2003
James R. Thompson - Illinois' longest serving governor, from 1977-1991
The Commission's Eight Topics:
Al Qaeda and the Organization of the 9-11 Attack
Intelligence Collection, Analysis, and Management (including oversight and resource allocation)
International Counterterrorism Policy, including states that harbor or harbored terrorists, or offer or offered terrorists safe havens
Border Security and Foreign Visitors
Law Enforcement and Intelligence Collection inside the United States
Commercial Aviation and Transportation Security, including an Investigation into the Circumstances of the Four Hijackings
The Immediate Response to the Attacks at the National, State, and Local levels, including issues of Continuity of Government
November 27, 2002 - President George W. Bush signs a bill creating the Commission. Bush also appoints Former Secretary of State Henry Kissinger to chair the commission.
December 11, 2002 - Former Senator George Mitchell, originally chosen by Democrats to be vice chairman, resigns, saying the workload would be too much and citing potential conflicts of interest with his law firm.
December 16, 2002 - President Bush appoints former New Jersey Governor Thomas Kean to chair the Commission.
March 31 - April 1, 2003 - First public hearings take place. The focus is hearing from victims and people impacted by 9/11.
May 22 - May 23, 2003 - Second public hearings take place. The focus is Congressional oversight and aviation security.
July 8, 2003 - The first interim report is released.
July 9, 2003 - Third public hearing takes place. The focus is "Terrorism, Al Qaeda, and the Muslim World."
September 23, 2003 - The second interim report is released.
October 14, 2003 - The fourth public hearing takes place. The focus is intelligence and national security policy.
November 19, 2003 - Fifth public hearing. The focus is emergency preparedness.
December 8, 2003 - Sixth public hearing. The focus is "Security and Liberty."
January 26 - 27, 2004 - The seventh public hearing takes place. The focus is border and aviation security.
March 24, 2004 - Former Counterterrorism Chief Richard A. Clarke testifies.
March 30, 2004 - The White House says it will allow National Security Adviser Condoleezza Rice to testify publicly before the commission investigating the September 11 terrorist attacks, so long as her appearance is not considered a precedent.
April 8, 2004 - Condoleezza Rice testifies in the morning - public and under oath. Former President Bill Clinton testifies in the afternoon. Clinton's testimony is not public or under oath.
April 13, 2004 - Former FBI Director Louis Freeh, Former Attorney General Janet Reno and current Attorney General John Ashcroft testify at the tenth public hearing. Former acting FBI Director Thomas Pickard and J. Cofer Black, former head of the CIA's counterterrorism center, also testify.
April 14, 2004 - CIA Director George Tenet and FBI Direct Robert Mueller testify in separate public sessions.
April 29, 2004 - President George W. Bush and Vice President Dick Cheney meet with the 9/11 Commission from 9:30 a.m. until 12:40 p.m., in the Oval Office at the White House. The President and Vice President answer questions but are not under oath. The meeting is not officially recorded. Two members of the White House counsel's staff are allowed to take notes during the session, as are the commission members.
May 19, 2004 - Former New York City Mayor Rudy Giuliani and former director of New York City's Office of Emergency Management Jerry Hauer testify before the 9/11 Commission.
May 27, 2004 - Original deadline to report on its findings.
June 16, 2004 - Commission holds its twelfth and final public hearing on its investigation into the September 11 attacks.
July 22, 2004 - The Commission releases its final report. The report said the original plot called for 10 hijacked planes, al Qaeda's role in the 1993 World Trade Center bombing was uncertain and there was no "credible evidence" of cooperation between Iraq and al Qaeda.
July 15, 2005 - It is announced that actors Hilary Swank and Kevin Costner will narrate the upcoming documentary film "On Native Soil: The Documentary of the 9/11 Commission Report." The film will tell some of the survivors' stories and will examine some of the commission's recommendations.
September 10-11, 2006 - ABC airs a dramatization based on the 9/11 Commission Report called "The Path to 9/11." It airs over two nights with limited commercial interruption. Governor Thomas Kean, chairman of the 9/11 Commission, serves as a senior consultant on the project.
July 21, 2011 - The Department of Homeland Security releases a report citing "significant progress" in fulfilling specific recommendations made by the 9/11 Commission.
August 31, 2011 - The heads of the 9/11 Commission release a report warning of gaps in terrorism prevention in the United States. The report, Tenth Anniversary Report Card: The Status of the 9/11 Commission Recommendations, highlights nine of the commission's recommendations that remain unfulfilled.
January 2012 - Despite the 9/11 Commission's directive to make most of their material available to the public by 2009, the records remained sealed at the National Archives and Records Administration (NARA).
April 12, 2012 - 9/11 Commission Co-Chairs Tom Kean and Lee Hamilton, now leaders of the Bipartisan Policy Center's re-launched Homeland Security Project, announce new members of the Project.
March 25, 2015 - The FBI releases its final report on the 9/11 Review Commission: The FBI: Protecting the Homeland in the 21st Century. The report discusses the FBI's implementation of the commission's recommendations.