Soldiers attached to Joint Task Force Guantanamo walk through Camp Delta at the U.S. Naval Base in Guantanamo Bay, Cuba March 22, 2016. During U.S. President Barack Obama’s historic visit to Cuba this week, he pushed Cuba to improve its record on human rights and sparred with President Raul Castro, while Castro hit back by decrying U.S. “double standards”. The Communist-led island frequently criticizes the United States on subjects such as racism, violence and the prison the United States maintains at its naval base at Guantanamo Bay in Cuba. Human rights remained an impediment to strengthening ties with Cuba despite the rapprochement reached by the two leaders in December 2014, Obama said, adding a "full flowering" of the relationship could happen only with progress on the issue. Castro offered Cuba's recipe for better relations – saying the two countries could achieve much better ties if the United States lifted its 54-year-old trade embargo on the island and handed back the Guantanamo base to Cuba. For decades, Obama's trip would have been unthinkable. It became possible after secret talks led to a 2014 agreement to normalize relations between the two Cold War-era foes. Obama has urged Congress to rescind the economic embargo but has been rejected by the Republican leadership. He had both Democratic and Republican elected officials with him on his Cuba trip and hopes Congress may act after the November 8 presidential election. (Photo by Lucas Jackson/Reuters)





A detainee watches television while being held in Joint Task Force Guantanamo's Camp VI at the U.S. Naval Base in Guantanamo Bay, Cuba March 22, 2016. (Photo by Lucas Jackson/Reuters)





Soldiers' hats rest on a table next to radios in Joint Task Force Guantanamo's detainee hospital at the U.S. Naval Base in Guantanamo Bay, Cuba March 22, 2016. (Photo by Lucas Jackson/Reuters)





An empty cell block is pictured within Joint Task Force Guantanamo's Camp VI at the U.S. Naval Base in Guantanamo Bay, Cuba March 22, 2016. (Photo by Lucas Jackson/Reuters)





A soldier puts on rubber gloves before interacting with detainees within a cell block that is a part of Joint Task Force Guantanamo's Camp VI at the U.S. Naval Base in Guantanamo Bay, Cuba March 22, 2016. (Photo by Lucas Jackson/Reuters)





Soldier are reflected in the window of Joint Task Force Guantanamo's Mental Health Unit at the U.S. Naval Base in Guantanamo Bay, Cuba March 22, 2016. (Photo by Lucas Jackson/Reuters)





Items not allowed to be brought within Joint Task Force Guantanamo's Camp VI sit in a cabinet at the U.S. Naval Base in Guantanamo Bay, Cuba March 22, 2016. (Photo by Lucas Jackson/Reuters)





A detainee stacks oranges into a pile while being held in Joint Task Force Guantanamo's Camp VI at the U.S. Naval Base in Guantanamo Bay, Cuba March 22, 2016. (Photo by Lucas Jackson/Reuters)





A National Geographic Magazine that has been defaced by inmates is shown in Joint Task Force Guantanamo's library at the U.S. Naval Base in Guantanamo Bay, Cuba March 22, 2016. (Photo by Lucas Jackson/Reuters)





A soldier shows entertainment options that are available to detainees in Joint Task Force Guantanamo's library at the U.S. Naval Base in Guantanamo Bay, Cuba March 22, 2016. (Photo by Lucas Jackson/Reuters)





Improvised weapons are displayed on a wall by Joint Task Force Guantanamo at the U.S. Naval Base in Guantanamo Bay, Cuba March 22, 2016. (Photo by Lucas Jackson/Reuters)





A sign identifies Joint Task Force Guantanamo's Camp V at the U.S. Naval Base in Guantanamo Bay, Cuba March 22, 2016. (Photo by Lucas Jackson/Reuters)





Color copies of detainee artwork hangs on a wall within Joint Task Force Guantanamo's Camp Delta at the U.S. Naval Base in Guantanamo Bay, Cuba March 22, 2016. (Photo by Lucas Jackson/Reuters)





The United States flag decorates the side of a guard tower inside of Joint Task Force Guantanamo Camp VI at the U.S. Naval Base in Guantanamo Bay, Cuba March 22, 2016. (Photo by Lucas Jackson/Reuters)





Chain link fence and concertina wire surrounds a deserted guard tower within Joint Task Force Guantanamo's Camp Delta at the U.S. Naval Base in Guantanamo Bay, Cuba March 21, 2016. (Photo by Lucas Jackson/Reuters)





The United States flag flies inside of Joint Task Force Guantanamo Camp VI at the U.S. Naval Base in Guantanamo Bay, Cuba March 22, 2016. (Photo by Lucas Jackson/Reuters)





A sign identifies Joint Task Force Guantanamo's closed down Camp I at the U.S. Naval Base in Guantanamo Bay, Cuba March 22, 2016. (Photo by Lucas Jackson/Reuters)





Medicines stand on shelves inside of Joint Task Force Guantanamo's detainee hospital at the U.S. Naval Base in Guantanamo Bay, Cuba March 22, 2016. (Photo by Lucas Jackson/Reuters)





An X-ray table stands on the opposite side of a radiation shield inside of Joint Task Force Guantanamo's detainee hospital at the U.S. Naval Base in Guantanamo Bay, Cuba March 22, 2016. (Photo by Lucas Jackson/Reuters)





A sample cell is displayed within Joint Task Force Guantanamo's Camp VI at the U.S. Naval Base in Guantanamo Bay, Cuba March 22, 2016. (Photo by Lucas Jackson/Reuters)





A soldier shows an arrow that points to Mecca inside of sample cell within Joint Task Force Guantanamo's Camp VI at the U.S. Naval Base in Guantanamo Bay, Cuba March 22, 2016. (Photo by Lucas Jackson/Reuters)





A soldier attached to Joint Task Force Guantanamo briefs visiting members of the media within Camp VI at the U.S. Naval Base in Guantanamo Bay, Cuba March 22, 2016. (Photo by Lucas Jackson/Reuters)





A protected television set hangs above a cell block within Joint Task Force Guantanamo's Camp VI at the U.S. Naval Base in Guantanamo Bay, Cuba March 22, 2016. (Photo by Lucas Jackson/Reuters)





A pain chart with writing in Arabic hangs on the wall inside of Joint Task Force Guantanamo's detainee hospital at the U.S. Naval Base in Guantanamo Bay, Cuba March 22, 2016. (Photo by Lucas Jackson/Reuters)





A soldier attached to Joint Task Force Guantanamo stands in the detainee library at the U.S. Naval Base in Guantanamo Bay, Cuba March 22, 2016. (Photo by Lucas Jackson/Reuters)





A soldier attached to Joint Task Force Guantanamo walks past a sign posted at the U.S. Naval Base in Guantanamo Bay, Cuba March 22, 2016. (Photo by Lucas Jackson/Reuters)





A detainee watches television while being held in Joint Task Force Guantanamo's Camp VI at the U.S. Naval Base in Guantanamo Bay, Cuba March 22, 2016. (Photo by Lucas Jackson/Reuters)





A detainee lifts a paper bag within Joint Task Force Guantanamo's Camp VI at the U.S. Naval Base in Guantanamo Bay, Cuba March 22, 2016. (Photo by Lucas Jackson/Reuters)