Interesting. Before I moved, I used to live in an old 150 year old Irish farmhouse (over 170 years now). It truly amazed me when making repairs to discover that the metre thick walls were also made up from wood twigs, boulders, soil and alsorts.
Also, inside each corner of the building an egg was carefully placed.
It all sounds quite strange compared to building regulations now, but it was a very sturdy house and I would think it will probably be standing in another 170 years.