How do I find the answer to the question below?

Question

Salonica is today a provincial city in a small country. For centuries it was the second city of a major empire. Little or nothing is now left of that heritage. What is it about the past of this city, however, that can provide lessons for the larger universe of European cities today?

Answer 1

http://www.google.com/webhp?source=search_app#q=Salonica+history

I'd look at how various ethnic group lived together.