Do GMCs care about their environment?

The spectacular luminous glow of a grand design galaxy confirms that the spiral arms are a popular place for star formation. Yet, is this simply because there is more gas in this region or do the properties of the star-forming gas differ significantly between galactic locations? The first part of this talk will examine a simulation of the grand design galaxy, M83, and compare the properties of the star-forming clouds in the bar, spiral and outer disc environments.The second half of this talk will look closely at interactions between gas clouds to explore whether these encounters could drive the formation of the most massive stars in the galaxy. By using an idealized model of two clouds, we will present the main properties affecting the formation of star-forming regions and speculate how common this is likely to be in the real Universe.