I like to use Google Earth to scan farm fields for signs of old (ancient in my case) settlements. When you live on the land, you change its soil composition and structure. Even after a thousand years and annual plowing, you can't hide the fact that soil has been disturbed by something different than the surrounding farmland. In the attached image (from Google Maps) I circled an area the shows the telltale signs that something was there long before. There are also two other faint colored areas, irregular shaped, that also are worth investigating. On Saturday I will go and detect on these areas and see what I find. If anything good - I will post it here.