The fascination with water mills, both tidal or river based abounds in literature. With the mill in the background, Victorian master painters record magical summer times. Mills tell us much about societies and their ability to harness natural forces. Although occasionally difficult to find now, as most are in ruins, many can still be identified all over Europe, sometimes hidden in rough ground or positioned in all their glory in an estuary.  Some have pre Roman origins.  In the eastern Algarve, there are examples of both types of mill.  This article focuses on tidal mills, which are typically in this region, horizontal, long buildings.  Many tide mills, along with watchtowers, fortifications, hermitages and…