Ah but as I recall (from a TV prog) the dark had occurred in smokey victorian times and there was no intention to ever have the new stuff blend in - so that future generations would know what had been done in our era, and something about it would be a permanent record of how much less smokey it was in the twenty first century...
Maybe the TV had it wrong because it sounds a lot of dollop to me, in fact i might just go up there and....
nah, better not.