This building is more than it appears. At the time of its construction, it was at the cutting edge of several key engineering fields, including climate control (the United States' biggest plant and the first automated plant with a comprehensive network of thermostats), elevators (world's fastest--fast elevators are crucial in a skyscraper), and garages (world's biggest).

It was built on stilts over a working railyard, and consequently was a landmark in the use of air rights. The fact that the yard's 21 tracks stayed open throughout construction, including foundation excavation (done by hand over three years!), is impressive in its own right.

It now is connected with 1990's Two Prudential Plaza, a neo-Art-Deco-ish faceted spire.

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