Abstract: The invention relates to a carbon-containing nanomaterial comprising, in particular made up as, a network of carbon wall structures which enclose open or closed voids which has a density which can be as low as 0.2 mg per cm3 or lower. The nanomaterial of the invention is made up as a network of carbon wall structures. The carbon wall structures can be tubular, rod-like or in the form of webs or the like which have varying thickness and thus form a network structure, in particular a three-dimensional network structure constructed in the manner of a sponge.