Concrete
From Tardis Wiki, the free Doctor Who reference
According to the newly regenerated Romana II, concrete was created by the addition of gravel to cement. The Fourth Doctor essentially agreed, and called it an indicator of civilisation on the mysterious planet on which they'd landed. (TV: Destiny of the Daleks)
A car factory in Arcopolis was made of diamond-reinforced type five space concrete. (PROSE: The Eyeless)
