Info is available at the wiki and a map will be posted soon (of course no details, we shouldn't make it easy for our enemies ).
The specification of the defences is very high, with extensive and interconnected bunker complexes for thousands of men. There are 57 main forts, 120 smaller forts and 467 casemates between, with over 250 kilometres of tunnels. Artillery is coordinated with protective measures to assure that one fort can support the next in line by bombarding it directly without harm. The largest guns are therefore 135mm fortress guns. Larger weapons are to be part of the mobile forces and are to be deployed behind the lines.