Everything from major cities to more remote areas in places throughout China, Europe, South America, Africa. etc. It would be nice to spend months at a time in different places, maybe learn some new languages and get some exposure to other ways of living and see the Great Wall, Rome, pyramids, etc. My first desination would be island hopping around the South Pacific and mountain hiking. I read an article in NatGeo on Tonga years ago that caught my interest. Now that I think about it, doing field work for Doctors Without Borders would be something I would look into. I have no medical training, but I'm sure they could use people with other skills.