Borgboda (also called Borgberget), located in Borge hill, Saltvik, is the largest hillfort in Åland with an area of total three hectares. When it was in use, around 1000 AD, the hill was surrounded by water on three sides. Steep hill was enforced with walls of stone and timber, remains of which can still be seen, along with remains of a few buildings. It is believed that Borgboda was never permanently inhabited, but functioned as a place where nearby people fled to when threatend.
The area near Borgboda s rich with prehistorical sites. There is a large iron age burial ground right before the hill, and sizable bronze age cairns are located just a few hundred meters north of 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.