In the parklike grounds of Jong Myo Shrine in Seoul, Korea, stones line the center vein of the pathways. It is instinctive to walk down the center of the lane.
However, it is NOT okay to walk on this Sillo, the passage for the spirits of the deceased. It was amusing to watch people begin strolling down the center of the path, then look at the sign (Korean or English), say "oops" or equivalent, and then sheepishly jump off the path. (I was one of those people).
Jong Myo Shrine - This dates to 1608. Ancestral tablets of kings and queens are behind these doors.
Doorway to a spirit chamber. The crack symbolizes the coming and going of the spirit (and allows for controlling the humidity, by the way).