The headquarters for Futurama's delivery service has been hiding in Liège, Belgium.
reddit user yearh made this gif from a photograph by Al Richardson (head over to Flickr to the image in its full-resolution glory). This is part of the Cointe Observatory built by the University of Liège in the late 19th century. It looks a bit less obviously like Planet Express when you see the surrounding structures:
Photo by Xofc, Wikimedia Commons.
Cointe Observatory housed the university's Institute of Astrophysics and Geophysics until 2002, and, according to Wikipedia, was occupied by Société Astronomique de Liège as of 2008. There have been plans to renovate the building, but no word on whether those plans involve transporting it to a future version of New (New) York.