Uster Castle was built probably around 1200 by the House of Rapperswil. After the Appenzell wars Hans von Bonstetten concluded a pact with Zürich, and became a citizen of the city of Zürich respectively claimed the so-called Burgrecht in 1407. From that moment, the castle in time of war could be strengthened by a Zürich garrison. As an Austrian vassal, Zürich guaranteed a neutral status to the Bonstetten family, particularly during the Old Zürich War when the neighbouring town of Greifensee was besieged and destroyed by Old Swiss Confederacy marauders; the bodies of the defenders were buried at the Uster church.
In 1492 a fire destroyed the castle. The owners changed the following centuries many times. In 1852 the castle became the seat of the district administration, and the tower was used as a prison. In the same year the castle was rebuilt, again, and a restaurant opened. Since 1995 the castle houses the private boarding school, and the former restaurant Burg was rebuilt in a steakhouse in 2009.
From the first construction phase, the lower section of the tower, up to the level of the upper floor of the today's boarding school's building around the tower base, is preserved, but never was scientifically examined, as well as the surrounding area of the plateau. The core of the present tower measures about 11 metres.
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.