Pianosa is the closest island to Elba, and offers an unique, splendid and absolutely intact atmosphere. Pianosa, as its name says, is the only completely flat island of the archipelago and has both rocky and sandy coasts, the main one of which is Cala San Giovanni (or Cala Giovanna), evocative white sand beach where there are also the ruins of a roman villa, called Villa of Agrippa, that was here exiled by the Roman Emperor Augusto. The island was inhabited since prehistory, but its archaeological treasure is represented above all by the catacombs of the 3rd - 4th century before Christ, when the Christian prisoners were condemned to work in the quarries of the island. In 1858 it instituted by the Granducato of Tuscany "la colonia penale agricola della Pianosa" and the condemned were sent here to take care of the fields on the island. In modern age Pianosa has become famous because of the presence of a prison for terrorists and members of the Mafia, closed in 1998, that has contributed to conserve the atmosphere uncontaminated. The presence of the prisoners, indeed, has kept the tourism away, protecting Pianosa, its nature, its reefs and its crystalline sea. Today the island accomodates only some partially free prisoners who work here, and some police officers.