Built by the Teutonic Knights in 1350, the Great Mill with its rising tiled roof is the grandest civil construction in Gdańsk. Until 1356 when the Radunia Canal was built, the mill was powered by slaves turning 18 huge wheels. It was the largest industrial plant in Europe during the Middle Ages and functioned until the end of WWII. Unfortunately, this treasure has since been turned into a shopping centre. At least there's a small exhibition of old equipment from the mill. The surrounding grain and flour stores, dating to 1400, are home to a few small shops.
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.