Example observations of the 20 km s^-1 cloud. Left panel: shows Spitzer IRAC data. Right panel: dust continuum emission near 280 GHz as observed by the SMA, combined APEX and SMA observations of the H₂H⁺ (3–2) transition, and APEX-only observations of the H₂H⁺ (3–2) transition covering a larger area. All panels are overlaid with contours of single-dish dust continuum emission at 870 μm wavelength from APEX at arbitrary chosen levels. We show SMA data not corrected for primary beam and missing extended emission to improve our visualization. The green circle indicates the location of an H ii region found by Ho et al. (1985), while green crosses indicate the location of water masers discovered by Lu et al. (2015).