A gabion system is disclosed which includes a gabion (1) for use in protecting military or civilian installations from weapons assault or from elemental forces such as flood waters, lava flows, avalanches, soil instability, slope erosion and the like. The gabion (1) comprises opposed side walls (2, 3) connected together at spaced intervals by a plurality of partition walls (4,5,6) such that spaces between neighboring pairs of partition walls define, together with the side walls (2,3), compartments (7, 8, 9) of the gabion, adjacent side and partition walls being connected to one another by pivotal connections (41) enabling the gabion to be folded between fully flattened and deployed configurations, the pivotal connections allowing the gabion to fold concertina-wise for storage or transport. The gabion system also comprises a fill material container (1001; 1005; 1015) configured to fit into and extend throughout a compartment (7, 8, 9) when the fill material container (1001; 1005; 1015) is loaded with fill material (1010; 1011; 1018).