Galaxy clusters magnify the images of distant galaxies which serendipitously 
lie behind them.  This gives us the opportunity to spatially resolve 
intrinsically faint distant galaxies in a level of detail which would 
otherwise require the increased light grasp and resolution of the next 
generation telescopes, still a decade away.  In this talk, I will show some 
recent results which utilize strong gravitational lensing to map the 
kinematics and distribution of star-formation within galaxies between z=2 
and z=5 on scales approaching 100pc using optical, near-infrared and sub-mm 
facilities.