The Cheapest Way To Fly To Europe?

I live in Chicago and I'm planning on doing a Euro trip this or next summer. I've been saving for years and I have money I just want to find the cheapest flight to Europe possible. The problem is every time I go to like Expedia or Orbitz it makes me put in a arrival city, but I don't care where I fly into, I just want the cheapest. Does anyone know what country tends to be cheaper to fly into from the U.S. or a website that says you the cheapest deals? Thanks in advance!