Overview of W49A in 1.6 GHz continuum emission (in color scale on the left panel; THOR; Wang et al. 2018) and GLIMPSE Spitzer IRAC 8.0 μm emission (right panel; Benjamin et al. 2003; Churchwell et al. 2009). White contours indicate cold, dense dust in 870 μm emission (ATLASGAL, Schuller et al. 2009; at levels of −0.24, 0.24, 0.8, 1.6, 2.4, 3.2, 4.0, 5.2, 8.0,16.0, 24.0, 40.0, 56.0 Jy beam−1). Large crosses indicate stellar clusters found with JHK imaging (Alves & Homeier 2003) while small crosses indicate individual O stars observed by Wu et al. (2016). The insert shows the Welch-Ring of ultra-compact H II regions (UC H II regions, Welch et al. 1987), represented here by contours of 5 GHz continuum emission (CORNISH survey, Hoare et al. 2012; at levels of 0.01, 0.02, 0.05, 0.75, 0.1, 0.125, 0.15, 0.175, 0.2, 0.25 Jy beam−1). The dotted inner ring indicates the shell structure found in this work (in good agreement with shells found by Peng et al. 2010); the outer ring indicates the approximate size of W49A. Labels in the left panel indicate main cm-continuum emission peaks (e.g., Dreher et al. 1984) and in the right panel indicate infrared star clusters (Alves & Homeier 2003).