“The Germans had conjured 26 divisions seemingly out of thin air,”
Patton’s own intel guys kept seeing some of the best Panser divisions getting pulled out of action and suspected they were doing that to amass them for a secret attack. They even correctly guessed the staging area from air recon tells.
:^) The intel from scouting detected staging areas loaded with armor and such, but besides Patton, everyone decided it was misIDed or otherwise just not worth concern.
The Ardennes? Sure, the Germans have run invasions through there twice in the 20th century and once in the 19th, but there’s no way they could do that again... ;^)
Hmm, sez here (wiki) that the freakin’ Vikings used Roman roads in the Ardennes in their pillaging in 881 and 882. :^D