I don't necessarily think there's a "most interesting," but I do think that people should be sure to read books that present differing cultures or experiences.
I remember reading "Hope and Other Dangerous Pursuits" by Laila Lalami. It changed my life. Books are small opportunities, each and every one. Some books offer opportunities to escape into worlds of magic and wonder or the 'small miracles' of the every day; but other books offer opportunities to stand in the shoes of others.
The former I enjoy, but the latter are the books I love. I think everyone can find something interesting in them!