Three-colour Herschel image of the Mon R2 molecular complex using 70 μm (blue), 160 μm (green), and 250 μm (red) maps. The shortest wavelength (blue) reveals the hot dust associated with H ii regions and protostars. The longest wavelength (red) shows the cold, dense cloud structures, displaying a filament network. The dashed rectangle locates the four H ii region area shown in Fig. 2.