  The signatures of UHE proton propagation through CMB are pair-production dip
and GZK cutoff. The visible manifestations of these spectral features are
ankle, beginning of GZK cutoff in the differential spectrum and E_{1/2} in
integral spectrum. Observed in all experiments, the ankle is usually
interpreted as transition from galactic to extragalactic cosmic rays. Using the
mass composition measured by HiRes, Telescope Array (TA) and Auger detectors at
energy (1-3) EeV, calculated anisotropy of galactic cosmic rays at these
energies, and the elongation curves we strongly argue against the
interpretation of the ankle given above. The transition must occur at lower
energy, most probably at the second knee as the dip model predicts. The other
prediction of this model, the shape of the dip, is well confirmed by HiRes, TA,
AGASA and Yakutsk detectors, and, after recalibration of energies, by Auger
detector. Predicted beginning of GZK cutoff and E_{1/2} agree well with HiRes
and TA data. However, directly measured mass composition remains a puzzle.
While HiRes and TA detectors observe the proton-dominated mass composition, as
required by the dip model, the data of Auger detector strongly evidence for
nuclei mass composition becoming steadily heavier at energy higher than 4 EeV
and reaching Iron at energy about 35 EeV. The Auger-based scenario is
consistent with another interpretation of the ankle at energy E_a=4 EeV as
transition from extragalactic protons to extragalactic nuclei. The heavy-
nuclei dominance at higher energies may be provided by low-energy of
acceleration for protons E_{max} \sim 4 EeV and rigidity-dependent E_{max}^A =Z
E_{max}$ for nuclei. The highest energy suppression may be explained as
nuclei-destroying cutoff.
