Deep within an unexplored marshland lies the ruins of what was once one of two capitals for an ancient race of angelic beings - the lost city of Scylese:

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Not quite sure where to go from here. I know the ruined rooftops make the buildings look like solid blocks, but not quite sure how to fix that without going over every house individually.

Aside from that, any advice or good ideas to improve the map before I let my players charge in like a herd of unstoppable elephants?