January 2002: First prisoners arrive at the prison camp set up in the U.S. naval base at Guantanamo Bay, Cuba. Detainees were initially sent to Camp X-Ray and later transferred to Camp Delta upon its completion in April 2002.
Aug. 4, 2003: This photo shows the interior of a prisoner's cell in Camp Delta on Guantanamo Bay Naval Base in Cuba. A total of 779 detainees have been incarcerated at Guantanamo Bay since 2002.
July 29, 2004: This photo shows a facility where combatant status review tribunals were to take place for detained enemy combatants on Guantanamo Bay U.S. Naval Base in Cuba.
Combatant Status Review Tribunals, or CSRTs, first began for detainees in August 2004. The tribunal involves three officers who present unclassified summary evidence against the detainee and question him about his role in the events. The three judge panel then decides whether the detainee is an enemy combatant or if he is releasable.
Dec. 6, 2006: In this photo, reviewed by a U.S. Department of Defense official, a shackled detainee is transported away from his annual Administrative Review Board hearing with U.S. officials, at Camp Delta detention center, Guantanamo Bay U.S. Naval Base, Cuba.
In 2006, a U.N. report recommended the closure of the detention center at Guantanamo Bay.
In June 2006, the U.S. Supreme court ruled 5-3 that the military commission system for Guantanamo Bay violates U.S. and international law, and that the Geneva Conventions apply to detainees.
Feb.11, 2008: U.S. Department of Defense charged Khalid Sheikh Mohamed, Ramzi Binalshibh, Mustafa Ahmed al-Hawsawi, Ali Abd al-Aziz Ali and Walid Muhammad Bin Attash for the Sept. 11, 2001 attacks under the military commission system.
In January 2010, the charges were withdrawn 'without prejudice,' according to the Defense Department -- a procedural move that allows federal officials to transfer the men to trial in a civilian court and also leaves the door open, if necessary, to bring charges again in military commissions.
In April 2011, the Obama administration gave up on trying the 9/11 suspects in civilian federal court in New York and will prosecute them instead before military commissions.
On Jan. 22, 2009, President Obama signed executive orders to shut down Guantanamo Bay detention facilities within one year. The White House later granted its Guantanamo closing commission extra time to study the situation.
But nearly two years later, Obama signed the 2011 Defense Authorization Bill that included strict new limits on the government's ability to transfer detainees out of Guantanamo Bay detention facilities. And on March 7, 2011, Obama lifted a two-year freeze on new military trials of terror suspects detained at Guantanamo Bay.
April 27, 2010: In this photo, reviewed by a U.S. Department of Defense official, a Guantanamo detainee does pull-ups inside an exercise area at the detention facility at Guantanamo Bay U.S. Naval Base.
As of Jan. 1, 2012, there were 171 detainees being held at Guantanamo Bay.
In September 2011, Director of National Intelligence James Clapper noted that the recidivism rate for transferred Guantanamo detainees continues to rise -- now at 26 percent, up from 25 percent in 2010 and 14 percent in 2009.
The annual cost of operating Guantanamo Bay is estimated to be between $90 million and $118 million.
Al Qaeda and Taliban detainees arrived from Afghanistan to be held at the U.S. Naval Base at Guantanamo Bay, Cuba on Jan. 11, 2002. The detention center has been the subject of controversy ever since.