The Heidetränk Oppidum near Oberursel is one of Europe"s most important Celtic oppida. The oppidum was surrounded by ramparts which encircled the settlement of opposite sides of a ravine called the Heidetrankthal. This imposing rampart where 10 km long and had six gates. The high point of the settlement was in the late La Tène period, but lost its importance in the mid first century BC. Archaeological finds from the Heidedtrank Oppidium include agricultural implements such as plowshares, hoes, scythe and sickle blades as well as tools and Celtic coins, particularly the so-called 'Nauheim Quinarius', which was probably coined in the oppidum itself.
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.