The one Greek island no one ever wanted to visit, long and narrow Makronisos was the worst island a political prisoner could be sent to between the 1920s to the 1970s (other islands, such as Ag. Efstratíos and Ikaria at least had something of a normal life amid the villagers). After the Second World War and Greek Civil War, it became the dumping ground for hundreds of the Greek resistance fighters, who were often tortured, physically and psychologically.
No one lives there on Makronisos today, but in 2019, it was declared a protected archaeological site, both as a memorial to the Civil War and because there are signs of a 4000 year old settlement; there are also several shipwrecks in the strait between Markonisos and Kea, including that of the HMHS Britannic, sister ship of the Titanic.
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