Antarctica, top of the list, the last true wilderness on Earth. Otherwise, various specific places are on the list. Cape Kennedy, Baikonur and Woomera (for the space connections); Vancouver, South Africa, Pategonia and pretty much all of Australia (for the wildlife); and certain parts of China while there is still steam running. Also Dargeeling, because one of my ancestors went out there, and I want to see the plantation he ran.
If it were possible, I'd like to take certain people to Tranquility Base (on the Moon) so that I could point to the footprints and laugh, but that's another story.