Photos

Ruins of Water "Roman" mill in Theabes.
There used to be a lot of them. Today there are only ruins waiting to be restored. This one is the most well preserved. It's located in Agioi Theodoroi district.

"A watermill is a structure that uses a water wheel or turbine to drive a mechanical process such as flour, lumber or textile production, or metal shaping (rolling, grinding or wire drawing).
The Romans used both fixed and floating water wheels and introduced water power to other provinces of the Roman Empire. So-called 'Greek Mills' used water wheels with a horizontal wheel (and vertical shaft). A "Roman Mill" features a vertical wheel (on a horizontal shaft). Greek style mills are the older and simpler of the two designs.

http://en.wikipedia.org/wiki/Watermill