I went there with my daughters last year, on a cold, windy day, and I had to remind myself that it is 5,000 years old and I shouldn't be disappointed that it seemed a bit small!
I saw a programme recently setting out the theory that Stonehenge, at least in part, had a medicinal function, in that people believed in the healing properties of the stones; and they described a man who seems to have journeyed there all the way from the Alps with his son (or some other close relative) to heal a terrible wound that he had, and was buried there when, unsurprisingly, it didn't work. What an astonishing and tragic waste of time and effort.
EDIT:
here is a newspaper report about the theory. The Amesbury Archer, that was the fellow.
How extremely stupid not to have thought of that - T.H. Huxley