The answer to this puzzle, which comprises 11 letters, is on the National Register of Historic Places.

Update Nov 14th: Yikes! This puzzle hasn’t fallen for anyone yet. The gravity of the situation is not yet too extreme, so we’ll just drop this hint here: some parts of this puzzle may evaporate.

Update Nov 23rd: Another hint — if you’ve solved this puzzle, you will have used each letter exactly once, in one way or another.