The assumption that you can avoid trolls simply by avoiding bridges is foolish and, if I may say, a bit culturally insensitive. Trolls thrive in many environments and indeed facets of our society. They are acutely intelligent, wield powerful magic and create some lovely music, if you can get past all the guttural cursing. If you must fight one, beware their disproportionate strength. O, and while there are in fact many trolls who make their homes under a bridge here or there, don't believe any that claim to be "guarding" the bridge. It's almost always just good old-fashioned extortion.
