devil’s on the doorstep

Thanks indeed to TYWKIDBI for giving us the chance to re-visit the engineering superstition (not pictured) that considered feats of medieval architecture so far beyond the capacity of human builders—especially bridges—that local populations would have had to enter into a diabolical compact in order to have their commission fulfilled.
Certainly encountering such marvels would have been rare and awe inspiring, but people, vastly under- estimating their own abilities, attributed them to more ancient, pagan times (the opposite direction from another bit of German lore, the Schwedenschanze (EN) that mistook ancient fortifications and earthworks to be remnants of the Thirty Years’ War with Sweden rather than traces of prehistoric humans).  During the Middle Ages even the relics of Roman roads were considered to be too logistically sophisticated and in excess of mortal requirements to not be the product of some Faustian bargain.  I wonder what sort of preconceptions are clouding our vision presently that we will only be able to dispel with hindsight.