Left: LABOCA 870-μm map of G1.87-0.14. The image is shown with linear scaling, and the colour bar indicates the surface-brightness scale in Jy beam^-1. The overlaid contours go from 0.27 Jy beam^-1 (3σ) to 1.62 Jy beam^-1, in steps of 3σ. Selected clumps are labelled with their designation (as listed in Table 3). The green plus signs indicate the positions of our C¹⁷O(2−1) observations (see Table 2). A scale bar indicating the 10 pc projected length is shown in the bottom left, with the assumption of a 10.57 kpc line-of-sight distance. The effective LABOCA beam of  is also shown in the lower left corner. Right: Spitzer 8-μm image towards G1.87-0.14 overlaid with LABOCA contours from the left panel. The image is shown with linear scaling, where the scale limits are based on the IRAF z-scale algorithm of the DS9 programme. The colour bar shows the surface-brightness scale in MJy sterad^-1. Note that not all IR-dark regions are seen in submm emission.