Abstract: Cushioning elements having a first plurality of parallel buckling walls and a second plurality of parallel buckling walls each comprising an elastomeric material. At least some of the buckling walls of the second plurality intersect and interconnect with at least some of the buckling walls of the first plurality. The elastomeric material comprises an elastomeric polymer and a plasticizer, and a ratio of a weight of the plasticizer to a weight of the elastomeric polymer is from about 0.1 to about 2.2. A height of the cushioning element is at least about 5 inches (12.7 cm). A mattress includes a core structure including buckling walls and a flexible material formed over the core structure.