A sketched diagram of the W51 region as viewed from the Galactic north pole, with the observer looking up the page from the bottom (i.e., W51C is the front-most labeled object along our line-of-sight). There are a few significant differences between this and Fig. 29 of Kang et al. (2010), particularly the relative geometry of the cloud and the H ii regions in W51 B. We also show a good deal more detail, revealing that there are H ii regions on both front and back of many clouds. The orange areas represent H ii regions and ionized gas (the W51 C SNR), while purple/blue/cyan regions show molecular clouds. The shapes of the clouds approximately reflect their shape on the sky, but these shapes are only intended as mnemonics to help associate this face-on view with the edge-on view of the real observations. Figure 12 shows the face-on view and can be compared side-by-side with this figure to get an approximate 3D view of the region.