Union Square, one of New York City’s major intersections, has quite a reputation. It is many things: a lively rallying site, a place to eat lunch or play a vigorous game of chess, a shopping center, a destination for hip eateries, and more. It’s hard to find anyone in New York who hasn’t enjoyed some aspect of Union Square.

Union Square had its humble beginnings in 1811, when the gridiron plan of Manhattan was approved. Originally named “Union Place” because it was the “union” of Broadway and 4th Avenue (formerly Bloomingdale Road and Bowery Road), it was created by the City Commissioner and formally became a public area in 1831.

It became a more welcoming space after renovations (partially done by Frederick Law Olmsted and Carl Vaux, who also designed Central Park) in 1872. While they intended for Central Park to be more natural and “romantic,” Union Square was specifically meant to be a more rigid, “public forum” kind of space.

Naturally, Union Square has both a rich history and fascinating current structures that are worth delving into. Read on to discover the secrets of one of the most popular, vibrant intersections in New York City.

15. The Mysterious Numbers in Union Square

If you were to walk out of the Union Square subway station and look around you, one of the first things you’d immediately notice is the large art piece and extensive digital clock on a wall at Union Square South. This installation, called Metronome, was one of the priciest private commissions of public art in New York City and still continues to confound passerby today, who often think it’s a national debt counter.

The wall sculpture itself has several components.The brick, ripple-patterned wall is called “The Vortex,” “The Relic” is the hand located at the top, the center hole that puffs steam is “The Infinity,” the gold specks on the wall are collectively called “The Source,” and the rock fragment, also on the wall, is “The Matter.”

The 100 by 62 foot Metronome has been here since 1999 and was created by Kristin Jones and Andrew Ginzel for a Union Square South developer, The Related Companies. The wall sculpture features a concentric circles that become progressively smaller as you go inward.

The hole in center of the circles expels large puffs of steam at noon and midnight with a burst of sound to mark the time. According to the artists, its purpose is to create “a dialogue between the public and their city as the eight elements evoke the city’s pulsing rhythms, daily rituals, and its astronomical and geological history.”

The digital clock, called “The Passage,” is a crucial component of the installation. As we’ve mentioned before, the numbers on the clock not only count the day’s 24 hours (shown on the rightmost seven digits), while simultaneously displaying how many hours are left in the day (shown on the leftmost seven digits). The center digit is a mesh of values coming from both sides. The clock uses military time and rounds to the nearest hundredth of a second.

With such a complex system, it’s not surprise that there have been a few mishaps. In 2010-2011 it ran forty minutes slow and consequently confused New Year’s Eve celebrants.