  We study topological defects arising in the Grand Unification Model
$SU(6)_L\otimes SU(6)_c \otimes SU(6)_R \times Z_3$. We show that the model
does not contain domain walls, while it produces massive magnetic monopoles and
it may, depending on the symmetry breaking chain, give rise to the formation of
strings. We also discuss their possible relation$ the origin of the highest
energy cosmic rays detected.
