Stars form from the gas and dust in molecular clouds via a series of complex processes that are currently only partly understood, and the evolution of these clouds drives the evolution of the stellar populations in the universe. Astronomers studying the formation of stars have, over the past decades, concentrated on a few select regions of active star formation: the solar neighborhood, the disc of the Milky Way, and the neighboring Magellanic Cloud galaxies. This range of environments is limited, however, and not representative of the conditions under which most stars in the Universe formed. For instance, the densities, pressures, and motions of the gas in these local environments are considerably lower than those thought to be present during the time of peak cosmic star formation about ten billion years ago. Moreover the disparate conditions make it difficult to untangle evolutionary effects.