  Recent measurements of hot and cold spots on the cosmic microwave background
(CMB) sky suggest a presence of super-structures on (>100 h^{-1}Mpc) scales. We
develop a new formalism to estimate the expected amplitude of temperature
fluctuations due to the integrated Sachs-Wolfe (ISW) effect from prominent
quasi-linear structures. Applying the developed tools to the observed ISW
signals from voids and clusters in catalogs of galaxies at redshifts z<1, we
find that they indeed imply a presence of quasi-linear super-structures with a
comoving radius 100~300 h^{-1}Mpc and a density contrast ~O(0.1). We find that
the observed ISW signals are at odd with the concordant \Lambda cold dark
matter (CDM) model that predicts Gaussian primordial perturbations at equal to
or larger than 3 sigma level. We also confirm that the mean temperature around
the CMB cold spot in the southern Galactic hemisphere filtered by a
compensating top-hat filter deviates from a mean value at ~3 sigma level,
implying that a quasi-linear supervoid or an underdensity region surrounded by
a massive wall may reside at low redshifts z<0.3 and the actual angular size
(16^\circ-17^\circ) may be larger than the apparent size (4^\circ-10^\circ)
discussed in literature. Possible solutions are briefly discussed.
