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 Odeon of Herodes Atticus is a stone theatre structure located on the southwest slope of the Acropolis of Athens. It was built in 161 AD by the Athenian magnate Herodes Atticus in memory of his wife, Aspasia Annia Regilla. It was originally a steep-sloped theater with a three-story stone front wall and a wooden roof made of expensive cedar of Lebanon timber. It was used as a venue for music concerts with a capacity of 5,000. It lasted intact until it was destroyed and left in ruins by the Heruli in 267 AD.
The audience stands and the orchestra (stage) were restored using Pentelic marble in the 1950s. Since then it has been the main venue of the Athens Festival, which runs from May through October each year, featuring a variety of acclaimed Greek as well as International performances.