Every crack in the sidewalk was glowing softly

I'm walking down a familiar suburban street, but the cracks between the paving stones are lit from underneath, like the ground is holding a thin river of light. I kneel down to touch one, and the whole block goes dark for a second, then the light pours back through a different crack a few houses down. I spend the whole dream walking from one glowing line to the next, never catching the source.