I'm getting to host an upcoming history radio show and would love to not sound too stupid, bland or even ignorant when asking questions. The fun gimmick in this show is that we'll be using a "time machine" to send someone back around 1900 to investigate and hopefully stop the upcoming world war. While not trying to sound too "what if" I want to focus more on the academic and facts. Forget that scenario, we want to get why WWI even started, and I want to ask questions that can bring informative answers.

I'm intimidated at the fact that I get to ask a seasoned history buff.

I've got an accredited mid-aged professor who just became excited about this idea. I've never covered history before, and I just want it to make it a great and informative experience for him, history buffs and non-history audiences alike.

What are some awesome questions I can ask him? E.g., I'll start with one, which emerging nation was the catalyst for WWI?

Edit: It gets tricky now because while we can touch on big political/familial hierarchies, we just don't want to focus on that because there are obviously awesome historiography accounts. The question is, what else?