  Deep, unbiased surveys are essential to decipher the cosmic evolution of
galaxies. The submillimetre (submm) and millimetre (mm) windows complement the
UV/optical waveband and are key to revealing the cold and dusty Universe.
Traditional ways of conducting deep surveys resort to either lensed fields or
target small areas for ultra-long integrations. These surveys have greatly
advanced our understanding of dusty star-forming galaxies (DSFGs), but are
susceptible to lensing uncertainties and cosmic variance and will be expensive
to expand. Here, we summarise our recent multi-wavelength survey of DSFGs in
the vicinity of ALMA's calibrators: the ALMACAL survey. These fields have
accumulated many hundreds of hours of on-source time, reaching depths and
effective areas that are competitive with bespoke cosmological surveys. We
summarise the multi-wavelength number counts from ALMACAL and the resolved
fraction of the Cosmic Infrared Background (CIB) from submm to mm wavelengths.
Meanwhile, combining all available ALMA observations in each field results in
impressive frequency coverage, which often yields the redshifts of these DSFGs.
The ALMACAL survey has demonstrated the scientific value of calibration scans
for all submm/mm and radio telescopes, existing and planned.
