After Hours

Geek Trivia: Monument alley

What ancient astronomic monument is accidentally and occasionally mimicked by the layout of New York City as described by the Commissioner's Plan of 1811, the urban planning document that defines modern Manhattan?

The ancient Greeks were a people of many fathers, at least according to their modern academic fan clubs. Hippocrates is considered the Father of Medicine, to the point that the "First do no harm" mantra recited by all physicians is called the Hippocratic Oath. Euclid is known as the Father of Geometry, or at least patron of the huge swath of the field known as Euclidean geometry. Homer is called alternately the Father of Epic Poetry and the Father of the Novel, such that any sufficiently poetic and epic work is described as Homeric. And, of course, there's Hippodamus, who gave the world the Hippodamian Plan.

Yeah, we probably lost you on that last one. Nonetheless, the modern world owes nearly as great a debt to Hippodamus of Miletus as we do the likes of Aeschylus, Father of Greek Tragedy; Herodotus, Father of History, or Aristotle, Father of... well... Modern Thinking.

Hippodamus, you see, is the Father of Urban Planning, and arguably the first great scholar of the notion that cities (and even societies) could be ordered, structured, rational objects. During his lifetime (498 BC to 408 BC), Hippodamus quarreled with Aristotle over the philosophical antecedents of patent law and counted among his clients Pericles, for whom he designed the harbor district of ancient Athens.

Hippodamus' namesake, the Hippodamian Plan, pioneered the grid layout of planned cities, as well as the distinctions between public, private, and sacred land. While grid-like city plans date back two millennia before Hippodamus, his writings on the subject define the features and rationale behind urban planning. It is this legacy that impacts the modern world in ways that few suspect. For an example, one needs look no further than contemporary New York City.

In 1811, the legislature of the state of New York adopted the so-called Commissioner's Plan, which laid out the bulk of land on Manhattan Island into its modern — and largely still intact — grid street layout. The vast majority of the city layout between Washington Heights and 14th Street is defined by the 1811 Commissioner's Plan, which is in turn directly derived from a Hippodamian Plan. Streets meet at regular intervals in right angles, and intersections near the shoreline are more common, as land there is deemed more valuable, thus requiring more traffic allowance and subdivision.

Yet, for all its Hippodamian origins, the Commissioner's Plan has a notable astronomic side effect, one that evokes an ancient monument whose earliest construction predates every planned city on Earth.

WHAT ANCIENT ASTRONOMIC MONUMENT IS ACCIDENTALLY MIMICKED BY THE COMMISSIONER'S PLAN THAT DEFINES THE LAYOUT OF NEW YORK CITY?

Get the answer.

About Jay Garmon

Jay Garmon has a vast and terrifying knowledge of all things obscure, obtuse, and irrelevant. One day, he hopes to write science fiction, but for now he'll settle for something stranger — amusing and abusing IT pros. Read his full profile. You can a...

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