Optical image of the centre of the Hydra I cluster obtained from the Digitized Sky Survey. The green squares show the region covered by the seven 6.8′×6.8′ FORS1 pointings from which we obtained the V and I photometry for our GC candidates, while the blue squares show the regions with U-band coverage. The dark blue inset shows the background field located outside the cluster in the direction indicated by the arrow. The dashed grey circle corresponds to a radius of 0.15 R_vir = 240 kpc.