Concrete

Concrete is a manufactured mixture of cement and water, with aggregates of sand and stones, which hardens rapidly by chemical combination to a stonelike, water-and-fire-resisting solid of great compressive but low tensile strength.

Concrete was employed in ancient Egypt (check this short article) and was highly developed by the ancient Romans, whose concrete made with volcanic-ash cement (pozzolana) permitted a great expansion of architectural methods, particularly the development of domes and vaults (often reinforced by brick ribbing) to cover large areas, of foundations, and of structures such as bridges and sewerage systems where water-proofing was essential.