The uprising in Athens, the centrepiece of the film, took place on 3rd December 1944 and lasted 37 days, ending when the Greek People's Liberation Army and the National Liberation Front effectively withdrew from Athens.
The "KKE" painted on the wall refers to the Communist Party of Greece (KKE).
Chios is the fifth largest island in the Mediterranean Sea, located just off the Turkish coast. After Greece was defeated in World War 2, Chios was placed under German control.