William Wilgus, New York Central Railroad's largely self-taught chief engineer, was the mastermind behind Grand Central Terminal's innovative engineering technology. With the plan for electrification and the sinking of the railroad tracks below grade, while building the new modern terminal, Wilgus also convinced railroad officials to commercialize the air above the new street-level decking. In leasing the area above the tracks to developers, the Railroad could increase its profits and create a bustling business district that surrounded, supported, and benefited from Grand Central Terminal.

Terminal City, as it was called, began to develop even before GCT was complete in 1913. Between 1909 when the Grand Central Post Office opened and the early 1930s when the Depression largely halted construction, the neighborhood boomed with hotels, apartment hotels, private clubs, and office buildings. Many of these structures were designed by Warren & Wetmore, one of the two architectural firms that created Grand Central. Most of the best-known hotels of Terminal City, including the Biltmore, Roosevelt, and the Commodore, were constructed by the mid 1910s, while the office buildings, including the Graybar and New York Central Buildings, were largely completed in the 1920s.

This walk does not propose to be a complete list of all Terminal City development. It does not include any post-World War II constructions and it concerns itself ONLY with some of the Terminal City structures that are still extant. Some of the buildings will be easily recognizable, while others, though technically the same structure, bear no resemblance to their former selves. So lace up some comfortable shoes and let's get exploring.