Billy Hayes, portrayed by Brad Davis, is an American university student apprehended while attempting to smuggle drugs out of Turkey. Sentenced to four years initially, his punishment is extended to a daunting 30 years.
Determined not to surrender to his fate, Billy collaborates with fellow inmates to devise an escape plan.
Interestingly, the prison setting depicted in the film was actually filmed at St. Elmo in Malta, not in Turkey.

Locations:

St Elmo, Valletta, Malta (Also seen in World War Z starring Brad Pitt)

Google Maps Co-ordinates: 35°54’09.8″N 14°31’06.1″E

Official Trailer