Do I Live In a Cave?

I have never heard anything about this. It was dedicated September 11, 2006 and I've never seen a picture or heard a thing about it until today.
It is titled "To the Struggle Against World Terrorism" and the best pictures and information I could find about it were surprisingly here at snopes.com. Apparently, I am not the only one a little dubious about a "monument" that I've never heard of. It seems to me a beautiful and thoughtful gesture. Why is it a secret?

Have you guys heard of it? Seen it?