Milestone

A milestone was a stone which marked the path to some destination, like a village, indicating proximity. Often bearing an inscription, these stones were placed alongside roads, to guide travellers along their way.

As evidence of history, standing still even as the landscape around them changed, the Third Doctor found some of these markers "fascinating". (PROSE: Doctor Who and the Sea-Devils)

Examples

On the island where the Master was being held prisoner, the Third Doctor pointed out an old milestone, which pointed out a way, in the fork in the road, to a settlement which had long fallen under the sea.

Clearing up the moss, which had collected over time, with a wire brush, produced from his pockets, he uncovered a name: Belial Village. Tired from walking, Jo Grant did not share the Doctor's enthusiasm about this ancient marker. (PROSE: Doctor Who and the Sea-Devils)

Behind the scenes

In the Editors' Notes for Decalog, the anthology was referred to as "a milestone in Doctor Who's literary history [...] [as it was] the first bona fide short-story anthology ever to be published."