Map of the 290 GHz continuum emission of PKS 1830−211, showing the two resolved lensed images of the blazar (left, contour levels every 0.1 Jy/beam, with the synthesized beam indicated as the dashed ellipse in the bottom left corner) and spectra of the fundamental 557 GHz transition of ortho-water extracted toward each line-of-sight (middle, normalized to the continuum level of each lensed image). An I-band image obtained with the Hubble Space Telescope, revealing the foreground z = 0.89 spiral galaxy, is also shown (right) with the same angular scale as the left panel. The two crosses indicate the position of the blazar images.