  Cosmic rays of energy higher than 10^19 eV may be explained by topological
defects produced in the early stages of universe. Two suitable alternatives
are: necklaces formed by magnetic monopoles connected by strings, and vortons
which are loops stabilized by superconducting currents. The former are
uniformly distributed in the universe, may account for cosmic rays above the
ankle, suffer a transient GZK cutoff with a subsequent recovery and isotropy of
observations is expected. The latter are concentrated in the galactic halo,
require an additional extragalactic contribution between the ankle and the GZK
cutoff, beyond which give a harder component and predict anisotropy related to
mass concentration.
