| The Antennae galaxies are the nearest spiral galaxies undergoing a major merger. The magnetic field orientations in this merging system are shown as the yellow line segments. The magnetic field is well aligned along the tidal tail in the south, making it the largest detected coherent magnetic field structure on galactic scales. The coherent field extends more than 20 kpc towards the south-east of the main bodies of the galaxies. The colour image traces various stages of star-formation activity in the Antennae galaxies with GALEX FUV shown in blue (tracing stars <100 Myr old), HST y-band in green (tracing stars >100 Myr old) and HST narrow band H-alpha in red (tracing stars <10 Myr old). The overlaid contours are the total intensity radio continuum emission at 2.8 GHz.