This has been bugging me for quite some time now. As one leaves Old Dingri and just before the climb to the mThong la starts there are these ... things in the way. For lack of a better word I call them 'forts' (cf. rDzong) but I'm not really sure what they are. They look ancient and are imposing even in their ruins - just too big to have functioned as a simple house. Furthermore, they seem to have been placed in strategic places as vantage points, and sometimes under a larger cliff to offer protection from the strong winds. But there is just too many of them to be militarily viable. You never lose sight of one before the next comes into view.
Note the care with which these walls were constructed. About three feet apart there is always a layer of stones. The only reason apparent to me is that since the region is prone to tectonic movement, these layers offer some kind of pliancy to the wall - it literally jiggles with the movement of the earth but it doesn't come down.
For the full view where these details are taken from go to the link above. And if you know anything on these strange walls, a bibliographical entry, learned guesses, anything - please do not hesitate to share it.