A protective structure for protecting a body from impact includes an inner layer of relatively flexible material, and which has a plurality of spaced-apart openings extending between opposite faces thereof and a corresponding plurality of protective units. Each protective unit includes a thin-wall, collapsible, fluid-tight enclosure with a volume of fluid filling the enclosure and at least one orifice in an enclosure wall that resistively vents fluid from the enclosure at a selected rate in response to an impact on the structure. The plurality of protective units are received in the plurality of openings so that corresponding first segments of the enclosures projecting form one face of the first layer together form a middle layer. Cooperating surfaces on the inner layer and each protective unit retain each protective unit in the corresponding opening in the inner layer. A method of making the protective units is also disclosed.