Another photograph of the Law Courts makes it evident that we are looking at one of two back-to-back tapers that cause the street to swell to a maximum width in the foreground. This makes for an open space right in front of one entrance to this imposing building. The taper creates an area that functions as a square, even though it is anything but square.
Notice that this street is quite busy with horse traffic. Congestion was, in fact, a serious issue in large by the end of the 19th Century. Horses and mules were the culprits - they occupy huge amounts of space and are unwieldy to maneuver, especially when it is necessary to back up. Manhattan apparently suffered from severe traffic congestion by the time the truck was introduced, which helped the situation for a while.
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