Filament network identified from galaxies (orange) compared with our fiducial reconstruction from the dark matter (DM) density field (dark red) for EAGLE at z = 0 showing the same 100 × 100 × 15 Mpc slice as in Fig. 2. The greyscale background represents the DM surface density, while indigo points and light blue circles denote galaxies with M_star > 10⁹ M_⊙ and haloes with M_200c > 10¹³ M_⊙, respectively. The galaxy-based network broadly captures the thicker DM-filaments, but misses most finer structures and suffers from a number of artefacts, examples of which are labelled as ‘A’, ‘B’, and ‘C’ (see text for details).