Farsickness —or "fernweh" from the German "fern" (far) and "weh" (pain) is when you yearn for a place you've never been, for the faraway. I heard about it on the radio, and a quick Google search shows me the word has been out there for a while. There are "Fernweh" t-shirts and "Farsickness" travel blogs.
Digging a little deeper I learn that the word "homesick" also entered our language from the German — "heimweh." It comes from a Swiss dialect and can also mean longing for the mountains. Ah, I think, just like Heidi. Remember when she's sent to Frankfurt and entertains Clara but all she wants is to go back and live with her grandfather on the mountain?
To have "fernweh" we need "heimweh." The familiar propels us to the faraway — then brings us home again.