United States' First Zoning Ordinance

There's a law in Baltimore said to be the oldest zoning restriction in the US; it dictates that no building on Mount Vernon Place can be taller than the top of the Washington Monument. I believe Philadelphia has a similar (but later) law regarding their monument to William Penn.

Still located at 120 Broadway in downtown Manhattan, the Equitable Building was constructed in 1915. At 42 stories, it towered over the neighboring farms and buildings, casting a 7-acre shadow. Citizens were obviously outraged at this, and thus pushed forward with the zoning laws that would establish rules for skyscrapers throughout the city, with the initial intent of preventing such buildings from depriving the surrounding areas of air and light. Though I could find no record of the law mentioned by Ground Control, I believe that this was the first regulation of its kind, meant to keep the quality of life for residents up, whereas the Baltimore and Philadelphia laws sound as if they were put in place to ensure that certain monuments were not dwarfed by surrounding buildings, as this would obviously diminish their value.