lord of the rings - Which earth locations most closely resemble locations from the works of Tolkien?

I hope this question survives and is not a dupe so I am happy to improve if required.

I know that Jackson and the film crew picked suitable existing locations but which real life places most closely resemble the style and architecture from the worlds of Tolkien especially those in which filming would have been barred, inaccessible or otherwise unworkable due to political, economic and infrastructure considerations.

Does a mountain citadel exist which can accurately be considered a real life Helms Deep? Is there a Lonely Mountain,a Lake Town, Mirkwood or Angmar on earth?