A foldable rectangular plastic/composite enclosure having first, second, third and fourth sides connected by hinges. The enclosure folds flat by rotating the sides on the hinges but is constructed to fold only in one direction. The hinges allow the enclosure to be folded flat for storage and transportation. The hinges are composed of a plurality of hinge members wherein each hinge member is positioned in a housing. The housing has an open interior which helps anchor the enclosure in the ground. An insertable locking pin can be inserted through each hinge to prevent the enclosure from folding. The enclosure can be made of plastic/composite imbedded with fibers such as carbon fibers, glass fibers, or ceramic fibers or imbedded with particles such as glass particles. The use of plastic/composite and various openings or cutouts makes the enclosure light weight.