Presents a color profile, with interpretation, of a radar scan which revealed Roman walls and surfaces, organic-rich Viking layers, and an intrusive barrel-lined well below an important redevelopment site. The technique proved an extremely informative and cost-effective means of evaluation. It uses bistatic continuous wave radar which gives precise depth-scaled stratigraphic information. A single day's survey at York produced an 81 Mb database, though on a more open site 500 Mb could have been obtained.