An airch is a structur that spans a space an supports structur an wecht abuin it. Airches appeared as early as the 2nt millennium BC in Mesopotamie brick airchitectur  an thair seestematic uise stairtit wi the Auncient Romans that wis the first tae applee the technique tae a wide reenge o structurs.
References[eedit | eedit soorce]
- "Ancient Mesopotamia:Architecture". The Oriental Institute of the University of Chicago. Retrieved 16 May 2012.