The Eifel aqueduct is a very important and valuable archaeological site, particularly for the study of Roman surveying, organizational ability, and engineering know-how (see the drawing for its route (red) >>>). 

There were four major areas of springs for this aqueduct:
* Grüner Pütz (Green plaster) between Nettersheim and Urft
* Klausbrunnen (Klaus fountain) near Mechernich
* An area of springs in Mechernich-Urfey
* The Hausener Benden in Mechernich-Eiserfey.

CA Eick was the discoverer of the farthest source from Cologne at Grüner Pütz near Nettersheim (in 1867; right and below). Information found at Wikipedia.

Part of the aqueduct near Gemünd. It, photo above ^, was used by the Romans to transport water from this place to Cologne.

This, now renovated, aqueduct was found near an old Roman fortress at Saalburg (near Bad Homburg). >>>