The basic miracle is stimulated emission, that if you shine a photon on an excited atom it can release another identical photon in the same direction and with the same wavelength.This is such a weird effect of quantum mechanics.
I like the part where they talked about sending light in vacuum tubes. It took a while before anyone managed to make optical fibers good enough. In fact, not long before the first practical optical fiber was demonstrated it was “proved” that it would be impossible to build one.
