During the Venetian rule, Ano Viannos was the largest village in the province of Belvedere, which was named after the Belvedere fortress. As a result, it was naturally well-fortified to protect against both external enemies and internal uprisings. At its western edge, the remaining ruins indicate the existence of a Venetian tower, which was later used by the Ottomans. This tower was destroyed during the Revolution of 1866.
South of Viannos, above Keratokampos, lies Kerato Hill, where the ancient city of Keraia is believed to have been located. On this hill, the Vigla Tower was built as a watchtower to serve as an early warning point. Its ruins are still visible today.
