There are a number places which embody the ideas of long now thinking: Nuclear waste repositories, historical sites, and other long term structures are all excellent places to look for long now inspiration. But there is one facility, though hard to gain access to, which is an amazing example of long term thinking, and it is not what you might expect.
Welcome to the underground bunker where the Mormons keep their genealogical backup data, deep in the solid granite cliffs of Little Cottonwood Canyon, outside Salt Lake City. UT.
Ladies and gentlemen, may I present to you: Crazy People With Too Much Money & Time.