[FW190]

"A couple of years ago someone unearthed the remains of a large Roman attempted retreat out of Germany where the entire Roman column had eventually been slaughtered over a miles long march."

Perhaps you're refering to "Battle of the Teutoburg Forest."

http://en.wikipedia.org/wiki/Battle_of_the_Teutoburg_Forest

Germanic warriors storm the field

Teutoburg Forest

Germanic tribes led by Arminius

[Moltke]

Teutoburg Forest

"In this picture we cannot see the Germanic warriors..."

How Not To Be Seen

[Ruy Dias de Bivar]

And as Augustus said many times later when he needed troops, and didn’t have them...

“VARIUS! GIVE ME BACK MY LEGIONS!”