4.5 $\mu$m in green, and 8 $\mu$m in red. Emission at 3.6 $\mu$m originates in a faint and diffuse PAH feature at 3.3 $\mu$m and in dispersed stellar light; the 4.5 $\mu$m band shows emission from Br$\alpha$ and Pf$\beta$ and vibrational H$_2$ lines and roto-vibrational CO lines, typical from shocked gas [e.g., @churchwell06; @watson08]. Emission at 8 $\mu$m includes strong features from polycyclic aromatic hydrocarbons (PAHs), which are prominent. PAH emission and ionized gas emission (shown by the H$\alpha$ and 1.46 GHz images) have different spatial distributions, with the ionized gas located in the inner area of the structures, closer to the excitation sources than PAH emission. PAHs cannot survive inside  regions [@cesarsky96], but they do on neutral PDRs at the interface between ionized and molecular gas. Thus, the emission at 8 $\mu$m shows that PDRs are widespread in this complex, a characteristic also indicative of the presence of molecular gas. PDRs are clearly delineated in this image (areas in magenta and white). The detection of CI radio recombination lines from several areas in NGC6357 is also indicative of the presence of PDRs (Quireza et al. 2006). The emission at 4.5 $\mu$m, coincident with the PDRs (detected at 8 $\mu$m) 