Multiwavelength light curve for Mrk 501 during the 2012 campaign. The bottom two panels report the electric vector polarization angle (PA) and polarization degree (PD). The correspondence between the instruments and the measured quantities is given in the legends. The horizontal dashed line in the VHE light curves represents 1 CU as reported in Aleksić et al. (2016), and the blue vertical dotted lines in the panels with the polarization light curves depict the day of the large VHE flare (MJD 56087).