Magnetars  are   the  strongest  -and  strangest  -   magnets  in  the
universe. They are the only cosmic objects we know of that are powered
exclusively  by  magnetism.  Their  activities include  persisting  in
X-rays  (and sometimes  in  the optical  band),  sporadic emission  of
short,  bright bursts  of  soft  gamma-rays, and  the  release of  the
so-called giant flares. With the latter activity, magnetars make their
presence  felt at  Earth from  across the  Milky Way  galaxy  as their
immense radiation can ionize  the Earth's outer atmosphere and disrupt
radio communications.  In this talk I will  review the characteristics
of  these exotic  objects and  highlight  some of  their prospects  to
fundamental physics.