... or so I'm told. It sits on gravel, and has only remained standing
as long as it has because the church invested in a complex water
management system, controlling the water level in the nearby rivers so
that the gravel doesn't get waterlogged, and the cathedral stays up.

There's a tour you can take of the cathedral, during which they take
you into the guts of the building, and during which I might perhaps be
able to find out more. I would like to do this.