ALMA has reached a major milestone by extending its vision fully into the realm of the submillimetre, the wavelengths of cosmic light that hold intriguing information about the cold, dark, and distant Universe. This achievement opens an entirely new window on the Universe for ALMA. It also is a critical step in the telescope's commissioning process, which brings its full capabilities to bear and makes them available to the international astronomical community. Here ALMA's band 10 receiver cartridge is seen, which is the shortest wavelength receiver developed for ALMA.