Which material is NOT a key Colosseum material according to the source?

• A. wood
• B. clamps
• C. stone
• D. iron

Answer: (A)

Wood is not listed among the materials that form the main, load-bearing structure of the Colosseum. The building relied on durable stone—primarily travertine limestone—for the exterior and much of the seating and walls, with a core of brick-faced concrete to create the vast arches and vaults. Iron clamps and metal joinery were used to connect and reinforce stone blocks, helping to distribute forces across the huge structure. Wood could have seen use in temporary scaffolding or interior work during construction, but it did not serve as a primary building material like stone, concrete, or iron.