How much of the planet Earth’s landmass remains unexplored? For example, are there still areas of South American or African jungle where modern explorers have still never set foot? By “modern” I mean explorers from the last few centuries, from whom we have fairly detailed records).
And how unlikely is it that somewhere in the vast North American forests there exists some small tribe of previously unencountered Native Americans? Is there even any forest left where “the white man” has still never tread?
I would think due to satellite photography there is almost nothing of any size (> 2m) not known on the Earth’s surface, even if not physically visited by mankind (i.e. areas of Antartica). Perhaps not everything is cataloged (so people can repeatedly ‘discover’ it), but I’d wager every surface feature (again of any decent size) has been viewed.
Very unlikely on the undiscovered tribe concept - it’s difficult enough to stay hidden even if you want to, impossible if you aren’t trying to hide…