Hellenburg Castle was probably built around 1300. After some renovations and additions, which took place in the 14th and 15th century, the castle got its final shape in 1450. The castle was lost as a result of a flooding caused by a storm disaster in 1477. In the 17th century nothing more remained than a ruin. These ruins were demolished in the 18th century, its stones used as building materials by the villagers of Baarland and the location of the castle was forgotten. The ruins were found accidentally in 1957. Today the foundations have been reserved.
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.