Ragnhildsholmen was a medieval castle built by Håkon Håkonsson (Haakon IV) of Norway around the year 1250. The castle was first time mentioned in 1275. In 1304 it was donated to duke Erik in 1304 and saw the power struggle between Swedish Kings Birger and Magnus III. After the near Bohus Fortress completed, Ragnhildsholmen lost its purpose. It was demolished and stones were probably used to build Bohus. Today impressive ruins still stands on the site.
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.