The sidewalk outside 101 Park Avenue is lined with brass plaques (the "podcast" on this site is worth listening to) depicting notable buildings in the area. Many of the architects who designed those buildings were once based out of the Architects' Building, which formerly stood on this site. Pictured is the Pan Am (now MetLife) Building, with the sculptures of Grand Central Terminal making an appearance in the foreground. Look familiar?
This is one of the eagles (designed by Adolph Weinman) that sat atop the original Penn Station before it met its untimely demise.