There are about 450 detainees still locked up at the US naval installation on Cuba, leaving US President George W Bush in the difficult position of trying to portray himself as a world leader of human rights while keeping people locked up for years without trial.
Bush has repeatedly said he wants to close Guantanamo but will not free detainees who continue to pose a security threat to the US and its allies, a position that has not satisfied human-rights organizations and foreign leaders who have pressured the White House to shut the facility.
UN Secretary General Kofi Annan as well as European leaders have urged Bush to close the prison camp.
Guantanamo has become the focus of accusations of human-rights violations since it opened in January 2002 amid images of detainees wearing orange jumpsuits strapped face up on stretchers being wheeled around in primitive Camp X-Ray - a collection of chain-linked open air prison cells at the time.
Camp X-Ray is now gone, replaced by Camp Delta, which looks more like a real prison, but Guantanamo's existence continues to haunt Washington and tarnish US credibility when it comes to human rights.
Guantanamo has ensnared Bush in a legal battle with US courts. Most recently the Supreme Court ruled that Bush's plan to try 10 detainees in military commissions was unconstitutional. The ruling has left the detainees' fate in limbo while Bush works with Congress to rewrite the law so the trials can proceed.
In the meantime, the Bush administration has released several hundred prisoners, and is now trying to figure out what to do with those who have not been charged with crimes but are still considered 'enemy combatants' facing indefinite detention.
About 120 of them fall have been categorized as no longer dangerous and offering little intelligence about the al-Qaeda network. Their release has been tied up in negotiations by the State Department and the Pentagon with possible destination countries - some of them home countries, others third countries.
A trickle of details coming out of Guantanamo, pried loose by human rights groups using federal open-information laws, has painted a picture of physical abuse and in some cases torture.
The revelations reinforced the shocking images from the US detention facility in Abu Ghraib, Iraq, where US soldiers snapped trophy photos of Iraqi prisoners being mistreated and sexually humiliated, and e-mailed them to family and friends.
Bush and US Defence Secretary Donald Rumsfeld maintain that all prisoners are being treated humanely and have vowed to punish members of the US military who abuse the detainees.
The number of detainees at Guantanamo, most of them captured in Afghanistan, peaked in its first year at about 800. Since then, several hundred have been released under reviews to determine which ones should be set free.
Last week, the Pentagon shipped Murat Kurnaz, a Turkish citizen, to Germany, where he grew up. In May, the Albanian government accepted five ethnic Uighurs the US long determined were eligible for freedom. The US had refused to return them to their native China over concern they would be abused.
The US Supreme Court ruled June 29 that Bush's plan to try the 10 criminally charged detainees was illegal under the US Constitution and Geneva Conventions.
The case was brought by Salim Ahmed Hamdan, Osama bin Laden's alleged bodyguard and driver who has been held at Guantanamo for more than four years.
The decision held that Bush did not have the authority to order tribunals and forced him to re-evaluate his approach, but he not relented in his determination to use the commissions.
