Stellar spatial distribution and observed colour-magnitude diagrams corresponding to two visually selected regions representative of the northwest (blue) and southeast (red) regions of the LMC. Left: LMC-reconstructed stellar density image from SMASH data showing the number density of stars brighter than M_i = −1. North is up, east is left. Middle: northwest region, roughly corresponding with the arm. Right: southeast region. We note the clear differences in the bright, blue main sequence (approximately delimited by the red ellipse), indicating the presence of a prominent young stellar population in the arm region (∼3.5% of the 8 million stars sampled against the only ∼0.7% of 7.3 million stars in the south region).