Hopefully that's just vague enough to be decent! I wasn't sure if the culprit should be known just yet (you know...for mystery!) so I left it ambiguous and open to discovery. I erred on the side of mystery!
So, the building I introduced...do whatever you want with it. Hera could be in there, Amazonian history, whatever. Something important that the League would want to destroy to ultimately break the Amazons, how about that? xD