Is Benzene rigid? Is there much flexibility to it? I thought no when I built the model but some people are saying it is rigid?

Each carbon atom in benzene is sp² hybridized, and the three sp² hybridized orbitals form three σ bonds with the two neighboring carbon atoms and one hydrogen atom. Each carbon atom has a π electron in the unhybridized 2p orbital. The six π electrons are delocalized above and below the benzene ring. For effective delocalization of π electrons, the six carbon atoms in the benzene ring are coplanar and thus the benzene molecule is rigid.

On the other hand, all C-C bonds in cyclohexane are single bonds. Since single bonds can rotate freely, cyclohexane molecule is flexible.