  We numerically study the head-on scattering of a 't Hooft-Polyakov magnetic
monopole and antimonopole for a wide range of parameters. In contrast to the
scattering of a $\lambda \phi^4$ kink and antikink in 1+1 dimensions, we find
that the monopole and antimonopole annihilate even when scattered at
relativistic velocities. If the monopole and antimonopole have a relative
twist, there is a repulsive force between them and they can initially be
reflected. However, in every case we have examined, the reflected monopoles
remain bound and eventually annihilate. We also calculate the magnetic helicity
in the aftermath of monopole-antimonopole annihilation and confirm the
conversion of relative twist to magnetic helicity as discussed earlier in the
electroweak case.
