I have incredible admiration for creativity, and especially when people follow their own particular (or even peculiar) vision. Take for instance Facteur Ferdinand Cheval who in his 40s found a beautiful stone by the road and was inspired to spend the next three decades creating the Palais Ideal. Ok, sure that tips over from 'vision' to 'obsession', but the legacy is remarkable. France seems to have its fair share of eccentric creators, case in point Robert Tatin's construction the Frenouse.
Here is a fabulous list of other folk art environments compiled by Kristin Fiore.