Unused Cardassian/Dominion shipyard
I was browsing through Forgotten Trek recently and came across this interesting concept. Greg Jein designed this concept art for an enemy station that was to be used in the first episode of the final season, and ultimately most of it wasn't used for cost purposes (among others). Greg was filling in for John Eaves at the time.
"If you think you're brave enough to walk the path of honor, then follow me into the dragon's den."