Cocev Kamen is a hilltop cave site of volcanic origin near the town of Kratovo. Objects (bone fossils) discovered near the cave suggest human presence since the Paleolithic. Authors agree that the site served as a gathering point for sacrificial rituals from the Neolithic, during the Bronze Age, throughout antiquity until the Middle Ages as clarified by an abundance of pottery shards, stone (flint) tools and bone fragments unearthed from the surrounding areas. Several caves and rock shelters are decorated with red figurative art work. Comparison with similar sites in Bulgaria and Italy suggests that the paintings are indeed prehistoric.
Debated remains the notion that Cocev Kamen has also been used as an (astronomical) observatory.
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.