concrete pillars (buildings, bridges)

concrete bunkers

concrete tunnels (or fill the tunnels with concrete)

concrete shoes

concrete dams

concrete walls

concrete sidewalks

concrete silos for missiles

evidence entombed in concrete

concrete evidence proving corruption

concrete jungle

The concrete operational stage of cognitive development occurs between the ages of 7 and 11.

"This system's gonna fall soon, to an angry young tune

And that's a concrete cold fact" sixto rodriguez