The ruins of the 14th-century Olsztyn castle are one of the biggest attractions of the area. The castle, located on a hill, among limestone rocks, is part of the Trail of the Eagles' Nests. It belonged to a system of fortifications, built by King Kazimierz Wielki, to protect western Lesser Poland from Czechs, to whom Silesia belonged at that time. For some time, as a fee, it belonged to Prince Wladyslaw Opolczyk. Taken away from him in 1396, the castle was then handed by King Wladyslaw Jagello to a local nobleman, Jan Odrowąż of Szczekociny. The castle was invaded several times by Silesian princes in the 15th century, and with the advancement of warfare, its fortifications became obsolete. In 1655, it was captured by the Swedes, and since then, it became a ruin. In 1722, it was partly demolished, with bricks used to build a parish church at Olsztyn. Currently, only fragments of defensive walls remain. The most impressive still standing part of the castle is a 35-meter round tower, built in the 13th century, which served as a prison.
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.