Mme. Zora,
Yes, thats a good question. Again, I don't have a strong belief in the conspiracy theories that trace the lineage way back to the Templars, but I am thoroughly entertained by them. I don't mean they are ridiculous, I mean they read like a much better thriller than the DaVinci Code. And they share with the Code the fact that the theory is based on hundreds of true things that probably do not all add up to the big claim, but it makes it really interesting.
As for buildings, there is tons of books and articles (all very controversial) on the architecture and layout of Washington DC. But that is in the 1700s and not what you were asking.
As for pre-1700s, there is a lot of interesting stuff from the 1600s because the Freemasons were a kind of underground organization at that time. There was even a time between the 1600s activity and the big "coming out" in the 1700s when the Masons were illegal. The really interesting thing is that during the 1600s, it looks like the founding members of the Royal Society in England were also an underground Masonic Lodge (this is controversial, of course). Why this is interesting is that the Royal Society was also a kind of underground organization because it was the formal beginning of the secular Enlightenment approach to the study of nature in a big way (this part is very true). Newton, Boyle, Lodge, Ward, and the great London architect Christopher Wren, and others were meeting in each other's homes forging the beginning of formalized empiricism.
This kind of activity was somewhat subversive but only in a cultural / religious way, not a political one. It would be popular opposition that would cause them to keep quiet about the fact that they were changing the rules in Natural Science by introducing mathematics, logic, and methodology at the expense of religion. So they laid low and did this until they gained enough political support to go public. At some point the Royal Society became chartered by the government and institutionalized science was born. By Darwin's time (mid 1800s), the Enlightenment was already in full swing and The Royal Society was one of England's crown jewels.
This might not sound that exciting, but it was one of the most amazing times in history, I think. Certainly, in some sense a new world order was being ushered in. So this is part of the "true" stuff.
So now, if you imagine that Templars who were still (hundreds of years after the fact) plotting revenge on the Catholic Church for its betrayal, you could easily imagine that the Royal Society could be part of their strategy. I doubt it highly, but if it were true, then it would have been a genius of a strategy. In terms of a lock on the intellectual world, The Enlightenment would flourish at the expense of the Catholic Church.
The other aspect of the strategy would be influencing the formation of the United States so as to create the perfect environment for Enlightenment ideals to flourish, protected from religion by the Constitution. It is true that most of the signers of the Constitution were Masons and that most of first 15 Presidents were Masons. The theory is aided and abetted by the wierd architecture and the seeming presence of Masonic symbology associated with our money and elsewhere.
Anyway, I don't wear a tin-foil hat about this. I just think it is the coolest conspiracy theory going. Even if it is not true, it is really full of genius.
So I guess the next question is "What about before the 1600s? Is there any architectural evidence that suggests the Masons existed before 1650 or so?", right?
I think there are a number of books around about that claiming all kinds of Masonic stuff on buildings that are much older than the 1600s, but I think these are highly controversial. But I am betting they are really fascinating. You could probably find them as easily as I could with Google and Amazon. I don't have any opinions or insight into which one's might have some valid stuff in them.
