Hachen Castle, built around 1000, initially owned by Count Ezzo, later passed to Otto von Northeim in 1060. In 1080, Otto's son gifted it to the Archbishop of Cologne, who granted it as a fief to the Counts of Dassel. In 1232, the Counts of Dassel sold it to the Counts of Arnsberg. After changing hands multiple times, it became property of the municipality of Hachen in 1839. The castle's significance waned from the 15th century onwards. Limited research on its architectural history includes findings from 1923 and 1978–1980, revealing a main castle area, bailey, shield wall, and various structures.
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.