The only buildings on Gyaros are the ones that were used when the islet was a place of exile. The imposing prison compound still stands tall on the peninsula between the 4th and 5th cove, along with the hospital, the power station and the scattered outposts. There is a clear view of the cemetery of the political prisoners but it is accessible only through a rough path. Most of the facilities that still exist today were built under forced labor by prisoners or exiles during the first post-war years.      

Gyaros is located at the sea area between Kea, Syros and Tinos. It covers an area of 17.5 km2 and its highest peak is the top of the Profitis Ilias hill at 489m. The coastline of the island stretches over 33km forming five natural harbors. Five concentration camps were built at the innermost points of each of these five harbors and housed prisoners between 1947-52, 1955-61 and 1967-74. After the fall of the Greek military junta and the restoration of democracy, Gyaros served as a shooting range by the Hellenic Navy.  The islet administratively falls under the municipality of Ermoupoli - Syros.  Gyaros is a single shale rock with rough and inhospitable terrain and sparse vegetation. Only sclerophyllous shrubs and garrigue grow on the islet. Two reptile species are the most characteristic of its fauna: Coluber gemonensis gyarosensis, an endemic snake subspecies and the lizard Cyrtodactylus kotschyi saronicus.