Found this on another history site, (on edit - actually looked it up again, and it's from a book review - off edit) a native Finn talking about the Winter War. I'd not heard this view - the line as far as I've heard/read was much more than a single trench and few bunkers. Anyone well read on the topic, with some insight into how accurate this idea is?
Quote:The myth of the Mannerheim Line is a fabrication by Soviet propaganda, after the disaster. The Finnish main defense line had about 15 concrete bunkers, the nearest about 3 km from each other, and a number of timber/stone bunkers on a line of 150 km. The "line" was a one trench line without depth. The Soviet intelligence had very good maps of the defenses, including bunkers. Intelligence did not overlook these, but military commanders did.
In Mannerheim's words later, "the real Mannerheim line was the men manning the line". But, the Soviets needed a reason for the failure. This fabrication of the Mannerheim Line is still maintained in Russian documentary sources and in living myth.