I'm currently running a D&D 4E campaign, and we ended the last session with the PCs chasing some raiders out of an old ruined cathedral. I have a backstory for the ruin, but since the PCs are new to the region I only want to offer them hints as to what it is (it's part of a much larger backstory that will be revealed as the campaign progresses). If I want the members of the party to recognize that what remains of the architecture is of Dwarven design, what skill would be best to test?

I was thinking Insight, History or Dungeoneering, but I figured I'd get some opinions here. Also, if there's some skill that you think would be more suitable, let me know what it is and why.

Thanks!