What exactly constitutes a Holy Ground in Highlander canon?
Most that I recall seem to be Christian burial places, but some were non-Christian burial places.
But pretty much ANY place is a burial after millenia of history, so does that mean any place at all can be (albeit, unknowingly) a Holy Ground?
Please note that the Highlander Wikia Holy Ground entry is not very helpful:
What exactly qualifies as holy ground and how an immortal can know the ground is blessed is never explicitly stated. There are cases of qualifying holy ground including land blessed by non-Christian faiths and clergy but there is no explicit statement as to how two immortals would know of a patch of ground's status unless it were indicated to be holy via markings etc.
So, what I'm looking for in a good answer would be a compilation of Holy Grounds from the entire canon with some proposed fitting pattern (or, better yet, a Word of God statement from someone connected to the franchise, but I will settle for a reasonably backed-up-by-source-material ruleset in the absence of such).
Incentive: A good answer showing a WoG source will likely earn you a post-factum bounty.