River no longer there but there's a straight road.
Cathedral is built on top of a hill so this river ran either next to the Cathedral or underground

So we know water, sound and light is involved in whatever they were doing.

No water within a mile and that water is at the bottom of the hill so the only way there possibly can be water at the top of the hill as that illustration suggests is from the road that I have said

I'm thinking they used one of these water mills to turn a mechanism within the cathedral.. powering something...
So the buildings didn't harness electricity from the ether, they used water as if you look at pyramids etc they are built next to water.
Nuclear power stations, next to water.

Water is the easiest way of collecting free energy, you only need to use a water wheel

Cologne cathedral, next to water

Barcelona cathedral next to water

York minster/cathedral next to water

Notre Dame next to water

The Milan Cathedral

The tides and flowing rivers are the most reliable and efficient free energy source of them all.
Simple technology, unlimited capability

Those buildings are always made of limestone too

I don't think the elites caused mud flood or whatever happened.
Everything points to a tsunami imo.
The fact ancient cultures were so obsessed with tracking movements of celestial bodies says to me that the resets are predictable and part of this system.
They take place maybe every few hundred years.

I'd also guess until the industrial revolution most of the population lived in costal regions.

Older generations knew and left warnings for future generations

Happy 🌞 worship day