Edessa is a small town (population 15,000) in central Macedonia (the Greek one, not the so-called country). It is located a few miles west of Pella, the ancient Macedonian capital.
This is the most well-known site in Edessa: The waterfalls constitute the landmark of the town. I took this picture back in 1987 (free to use for non-commercial purposes).
You may want to visit this site for more info (both in Greek and English).
Here is how Edessa appears from an altitude of 2.3 km (a Google Earth satellite image):
