Photo by myself, around 18th Street and Park Avenue South.
Looking north up Park Avenue, the MetLife building can be seen in the distance. The building looks like it's sitting on top of Grand Central Terminal (barely seen here) but is actually just north of it.
Park Avenue rises up and whips around Grand Central Terminal and under the MetLife building on something called the Park Avenue Viaduct. At one point cars are elevated above Park Avenue and it's a dramatic view. If you ever have the chance, I suggest a quick ride in a cab because it's kinda cool.
Related posts: On New York Buildings High and Low, Dusk Among Towers and Hovering Above Park Avenue.