Jeferson Memorial Sinking

So reports the Washington Post:

Underground, though, the problems may be huge: Slowly, almost imperceptibly, parts of the complex seem to be sinking into the mud.

It's probably not endangering the majestic 32,000-ton domed structure itself, although it's being monitored for movement.

The big problem seems to be a section of the sea wall that is breaking from the memorial's plaza and settling into the Tidal Basin. The "ring road" along the memorial's circumference also seems to be shifting, officials say.

Such movement is an alarming -- and chronic -- problem at the Jefferson Memorial, which was built in the late 1930s and early 1940s atop pilings and caissons sunk into an artificial mud flat that is about 100 feet deep. Engineers have been struggling for decades to keep everything firmed up.

It reminds me of the Cathedral on the Zocalo in Mexico City, which has been sinking for many years. It's my understanding that after extensive work over more than a decade, it's now sinking at a uniform rate throughout.

I guess that's progress.