Anonymous ID: 781b2a July 6, 2022, 6:15 p.m. No.16652543   🗄️.is 🔗kun

>>16652443

It is true that Egyptian, Babylonian, Greek and Assyrian civilizations used arches for underground structures such as drains and vaults. However, it was the Roman civilization (1000 B.C.E. - 500 C.E.) that first began using a keystone (also called a capstone) in their arches. The keystone is the topmost stone in the arch.