US military guards move a detainee inside the detention center in September 2010. At its peak, the detainee population exceeded 750 men.
Muslim detainees kneel during early morning prayers in October 2009. Cells are marked with an arrow pointing in the direction of Mecca, which is regarded as Islam's holy city.
A soldier stands near the fence line in January 2012.
A Quran sits among a display of items issued to detainees in September 2010. The suspects are given a prayer mat and a copy of the Muslim holy book as well as a toothbrush, soap, shampoo and clothing.
A guard walks out of the maximum-security section of the detention center in September 2010.
A police dog undergoes training exercises in October 2009.
A camp librarian views artwork painted by detainees in September 2010.
A detainee rubs his face while attending a "life skills" class in April 2009.
A seat and shackle await a detainee in the DVD room of a maximum-security detention center in March 2010.
US Marines join in martial-arts training in September 2010.
Members of the military walk the hallway of Cell Block C in the Camp 5 detention facility in January 2012.
Guards move a detainee from his cell in Cell Block A of the Camp 6 detention facility in January 2012.
A detainee waits for lunch in September 2010. The cost of building Guantanamo's high-security detention facilities was reportedly about $54 million.
Marines get an early morning workout in October 2009.
A bus carries military guards from their night shift in September 2010.
A military guard puts on gloves before moving a detainee in September 2010.
Members of the military move down the hallway of Cell Block C in the Camp 5 detention facility in January 2012.
A guard holds shackles before preparing to move a detainee in September 2010.
An American flag flies over Camp 6 at Guantanamo in June 2013.