You might be surprised, and horrified, to find out a not insignificant number of still standing buildings were built with no foundations. On a wing and a prayer, if you will.
Came across a house a year or so ago. The back half of the house was supported by an old tree stump. The person living there said the kitchen had an odd slope in the middle of it :)
I worked on a house where the previously built extension to the rear had been built over a soil pipe that let out into the ground, over the ~20 years since it had been built, it had tipped further and further and started to pull away from the house as the ground was eroded until we had to come in and knock it.
nice! I had one where I failed an inspection. Inspector comes out and signs off on the new job. "hey isnt this YOUR signature from the first time? Why did you sign off on it then if it is so wrong now?"
You can't imagine it because those bridges and cathedrals collapsed (and were probably rebuilt).