A very similar thing once happened to me, I was walking in Church Street in Liverpool City Centre next to Dixons.
They're used to be a concrete canopy that hung over the pavement and people would walk underneath it.
Here's a picture:
I was walking underneath it when I heard a smash very close to me. At first I thought it was box of eggs that had been thrown. I turned around to see what the noise was when I saw it, a large chunk of concrete had fallen out of the canopy.
It narrowly missed me by a foot, the block was about six inches thick, six inches wide and a foot long. I carried on walking. The people around me gasped and stood amazed at how lucky I had been.