Going on map oddities rather than strange (or smutty) place names, which is more than adequately covered in other threads:
If you use Google Maps, and you zoom in on Clitheroe in Lancashire, you will see what appears to be a legend for a village called "Great Britain", although I have seen another post that puts it to the West of Halifax. As you zoom out, it remains there until almost all of the UK fits on your screen, and then disappears, at a point that Manchester, Birmingham and London are still notated. As is the legend for the political entity known as the United Kingdom.
Why? Not sure, although it appears to be there as this is the geographical center of Great Britain.