Mile Markers

Knowing where you are, and where you are going, depends on a dizzying array of tools including maps, aerial algorithms, and global positioning satellites.  Earlier journeys were undertaken using rudimentary directions passed from person to person, with only a few scattered markers to verify the correct path.
The first markers were cairns of stone, stacked in various ways to indicate the correct fork or the presence of a special feature nearby.  The Romans elaborated on these stones to carve obelisks from granite or marble. They created durable roads for the timely delivery of supplies and armies, and clear signage assisted their competent engineering.  Road crews placed a cylindrical stone every thousandth double-step from the Appian Way to the very edges of the Empire.  Place names and distances were not always included; some mileposts carried only the name of the Emperor and the distance from Rome. The Golden Milestone (Milliarium Aureum) was erected in the Forum, marking the presumed center of the world.
There are many examples of historic mile markers in Britain, from the simplest tombstone carved by locals to cast iron whimsies with details highlighted in stark white and black paint.  The most prevalent distance markers in current use are found on the national motorways.  In the United States, aluminum mileposts are placed beginning at the southern and western boundaries of each state line.  These driver location signs provide a landmark so that stranded motorists can call for help.  Canals, rivers, rail lines, and other modes of transportation have similar signposts for safety and orientation.
The Zero Milestone in Washington, D.C. was inspired by the Golden Milestone; it established the point from which all road distances were calculated in America.  Each city has a single point to which all distances are measured on highways, usually a post office or city hall.  In New Orleans, the zero point is the U.S. Customs House on Canal Street, New York Cityuses Columbus Circle, and in London the prime reference point is not at Greenwich, but a plaque at Charing Cross.  Kilometer zero in France is a stone compass embedded in the cobblestone plaza in front of Notre Dame; in Cubaa 25-carat diamond (since 1973 a replica of the original once owned by Tsar Nicholas II of Russia) lies in the floor of El Capitolio.  What is the central point of your city?