The former First Lady was there to illuminate the plight of the Beaux Arts railway station that once dazzled New Yorkers and was, upon its opening in 1913, considered one of the city’s greatest wonders. Intended by developers to dwarf the nearby Penn Station, Grand Central Terminal cost nearly $160,000,000 (more than $4 billion today) to construct and was a front-page story in the local papers for weeks leading up to opening day. As dependence on rail travel diminished in the mid-20th century, Grand Central’s relevance too was questioned, and in 1963, the top of the station became the base for the tower known as the Pan-Am building, named after the airline headquartered there.

In 1975 a plot was hatched to dwarf the Pan-Am building with an even larger structure designed by famed Modern architect Marcel Breuer, but there was a problem: the sting of Penn Station’s demolition in 1964 was still fresh in the minds of many New Yorkers. In the aftermath of that legendary building’s destruction, Grand Central had been designated a New York City Landmark under a new law that gave the city the power to protect buildings it deemed worthy. When plans for the Breuer addition were presented to the Landmarks Preservation Commission, the response from officials was that the tower was essentially an “aesthetic joke.”

While few doubted the significance of Grand Central, the terminal’s owners took issue with the law itself—how, they wondered, could it constitute anything other than an unreasonable violation of their rights as property owners? Preservationists like Onassis, working with groups like the Municipal Art Society, continued to insist that saving Grand Central and buildings like it wasn’t a mere real estate matter, but an issue of public good. On June 26, 1978, the United States Supreme Court agreed with them in Penn Central Transportation Co. vs. New York City, not just in regards to Grand Central but in the spirit of the Landmarks law itself, with Justice William Brennan writing that to rule in favor of the building’s owners would “invalidate not just New You City’s law, but all comparable landmark legislation elsewhere in the nation.”