Thankfully, some of Beijing's alleyway architecture is protected these days, with buildings marked by white stone plaques.

BBC: Old Beijing at its timeless best

In ancient Egypt, pairs of tapering stone towers called pylons marked the entrances of temples.

ECONOMIST: Monitor

Fresh drops speckled his windshield as he turned in to his neighborhood, through a break in the stone wall that had once marked the bounds of the farm.

NEWYORKER: Outage

Mr Duncan starts with a Stone Age astronomer who observed the phases of the moon, and marked them by carving notches on an eagle's bone.

ECONOMIST: Late for the date