But wait! --- There's more!
Again, in 1971, my mate & I ran a bit short on money whilst budgeting for our UK trip, so ended up with it being a "working holiday".
One job we had was interesting:
A nice big warehouse was built in Southampton, quite close to the Solent.
As these places do, it had a very large concrete "raft" floor.
Over time, the Solent did what waterways are wont to do, & liquified the soli under the building.
This resulted in the centre of the floor sagging, but the edges stayed where they were supposed to be.
The result looked like a huge, shallow, "pie dish"!
Our job, along with a bunch of other people, was to move all the heavy stock into the centre of the floor.
Guys with pneumatic drills then cut around the outer edge, so the whole lot could settle back down to the new "ground level"!
It must have worked, as we never heard any more about it.