  Using a new compilation of available data on galaxy clusters and
superclusters we present evidence for a quasiregular three-dimensional network
of rich superclusters and voids, with the regions of high density separated by
about 120 Mpc. We calculate the power spectrum for clusters of galaxies; it has
a peak on the wavelength equal to the step of the network; the excess in the
amplitude of the spectrum over that of the cold dark matter model is by a
factor of 1.4. The probability that the spectrum can be formed within the
framework of the standard cosmogony is very small. If the cluster distribution
reflects the distribution of all matter (luminous and dark), then there must
exists some hithero unknown process that produces regular structure on large
scales.
