Vast nurseries that are giving birth to thousands or even millions of stars highlight the spiral arms of these galaxies imaged by ALMA, a telescope array in Chile. Clockwise from top left, the galaxies are Messier 100, Messier 66, and Messier 61. M66 has been disturbed by a gravitational encounter with another galaxy, which squeezed its gas clouds to the point that they began forming more stars. [ALMA (ESO/NAOJ/NRAO); NRAO/AUI/NSF, B. Saxton]