  The Pierre Auger Observatory is the world's largest operating detection
system for the observation of ultra high energy cosmic rays (UHECRs). The
detector allows detailed measurements of their energy spectrum, mass
composition and arrival directions of primary cosmic rays in the energy range
above $10^{17}$ eV. The data collected at the Observatory over the last decade
show the suppression of the cosmic ray flux at energies above $4\times10^{19}$
eV. However, it is still unclear if this suppression is caused by the
propagation of cosmic rays or rather by energy limitation of their sources. The
other puzzle is the origin of UHECRs. Some clues can be drawn from studying the
distribution of their arrival directions. The recently observed dipole
anisotropy has an orientation which indicates an extragalactic origin of
UHECRs. The Auger surface detector array is also sensitive to showers due to
ultra high energy neutrinos of all flavours and photons, and recent neutrino
and photon limits provided by the Observatory can constrain models of the
cosmogenic neutrino production and exotic scenarios of the UHECRs origin, such
as the decays of super heavy particles. In this paper the recent results on
measurements of the energy spectrum, mass composition and arrival directions of
cosmic rays, and future prospects are presented.
