I can't believe I didn't know until two days ago that Boston depends on groundwater to keep the pilings of some of its oldest buildings from rotting like the roots of drought-starved trees as the one-time tidal flats overlaid with landfill into which they were driven dry out.

"Our church's one foundation is pilings in a swamp:
the sextons check them weekly to make sure they're still dahmp.
For if we should get dry rot, our towers all would fall,
and there would just be rubble where now stands Mosley Hall."

(Church of the Advent parody of "The Church's One Foundation": verse 1.)

(I hope somebody's still checking them weekly, anyway.)