The Old Venetian Fortress of Corfu covers the promontory which initially contained the old town of Corfu that had emerged during Byzantine times.
Before the Venetian era the promontory, which lies between the Gulf of Kerkyra to the north and Garitsa Bay to the south, was defended by Byzantine fortifications which the Venetians largely replaced with fortifications of their own design. As part of their defensive plans the Venetians separated the promontory from the rest of the city of Corfu by creating the Contrafossa, a moat which is a sea channel connecting the Gulf of Kerkyra to the North with the Bay of Garitsa to the South, converting the citadel into an artificial island.
The fort successfully repulsed all three major Ottoman sieges: the great siege of 1537, the siege of 1571 and the second great siege of Corfu in 1716.
In 1718 lightning struck the powder magazine at Castel da Mare causing an explosion which created a chain reaction during which three secondary ammunition facilities also exploded, this in turn destroying most buildings inside the castle including the palace of the Captain General of the fortress, and many city buildings. Commander of the fortress and hundreds of others died in the explosion.
The fortress houses today the Public library of Corfu which is located in the old British barracks. The fortress grounds are also used for various types of art and culture exhibits. The Hellenic Music Research Lab of the Ionian University is also located at the Old Fortress.
References:The ancient Argos Theater was built in 320 BC. and is located in Argos, Greece against Larissa Hill. Nearby from this site is Agora, Roman Odeon, and the Baths of Argos. The theater is one of the largest architectural developments in Greece and was renovated in ca 120 AD.
The Hellenistic theater at Argos is cut into the hillside of the Larisa, with 90 steps up a steep incline, forming a narrow rectilinear cavea. Among the largest theaters in Greece, it held about 20,000 spectators and is divided by two landings into three horizontal sections. Staircases further divide the cavea into four cunei, corresponding to the tribes of Argos A high wall was erected to prevent unauthorized access into the theatron and may have helped the acoustics, but it is said the sound quality is still very good today.
Around 120 CE, both theaters were renovated in the Roman style.