An erectable barrier's basic unit comprises a base configured to rest on a ground and a movable hurdle pivotally connected to the base and configured to be in a resting position and in an active upright position. The movable hurdle comprises a first movable hurdle portion and a second movable hurdle portion parallel one to the other, and connected by at least one connecting rod. An erectable barrier comprises a plurality of erectable barrier's basic units connected one to the other by at least one connector.