That depends on which "miracle" we're talking about. South sea islanders probably thought it was a miracle the first time they saw someone fire a gun or the first time they saw an airplane fly overhead.

We know it wasn't a miracle, because we're familiar with guns and airplanes.

I'm suggesting that there are things which most of us aren't familiar with yet, things we may know nothing about, and would be astounded by when and if we encountered them. Yet there would still be a natural explanation, providing one understood the nature of what one was seeing.