what does this ! mean when next to abridge on the map?

[pavane]

hi
I have looked at the hex info box before I posted my query and had a good look through the manual. But I couldn't see anything that referred to !
Movement across the bridge doesn't seem to be affected.
My guess is it indicates
1 fortification,obstacles or mines are present
2 the bridge is set up for demolition and can be destroyed anytime by the owning player.
3 As you say it could mean it damaged.

Thanks for your suggestion. pavane