It's - it was a man-made structure, but any man-made structure, I'm sure to say any good civil engineer, is going to tell you, you - there's contingency plan you have...

NPR: In Tenn. Town, A Muddy Christmas For Some

To overcome all this, LeRoy Olson, an engineer at the University of Washington, devised a barrel-shaped structure of metal rings.

ECONOMIST: 20,000 leagues under the sea