Left panel: map of Gaia DR2 stars in an area of 0.31 × 0.30 degree² centred on the Galactic GC M3 (NGC 5272). Different colours highlight stars within twice the cluster r_c (red filled circles), once (grey filled circles), twice (yellow filled cicles), three times (cyan filled circles) the cluster half-light radius (r_h = 2.31 arcmin), andbeyond three times r_h (magenta filled circles). The RR Lyrae stars observed by Gaia in the cluster (159 of the 222 RR Lyrae stars known in M3) are marked as large black filled circles. The M3 centre coordinates and r_c, r_h values are taken from Harris (1996). Centre panel: G vs. G_BP–G_RP CMD for stars within twice the M3 r_h. The colour-coding is the same as in the left panel. Right panel: same as in the centre panel, but for the cluster G_BP vs. G_BP–G_RP CMD.