Now There's a Tail
This shows what happens when you get too close to the edge of the Grand Canyon. The full sign reminds you to "Use caution near the edge," or, if you're Canadian or French, "Prudence près du bord."
Note that the danger is not to the Canyon, which is robust, impressively deep, and can take care of itself.
"Spot the Blue:" I have updated this feature with additional photos.