Notes:

Has since been posted here and here in half resolution without text overlaid, though previously it was an easter egg on the website.

In the archive of the site, click on the manhole to see the image.
In more recent versions of the site, it goes to a trailer instead.

The url has /regions/us/ in it, implying that there are regional variants of the image, but if you manually change the region they all look the same (though the url variants do exist, it doesn't just accept anything).

Seems like I forgot to post this when I first found it, guess I was leaving people time to find secrets on the site themselves. Anyway, here it is.