Most stars in our Galaxy form in clusters which often contain massive stars. With their prodigious energy output, it is these massive stars which dominate the evolution of the interstellar medium. Understanding how these clusters and the massive stars within them form and evolve is one key of the questions for astrophysics. A major challenge in this field is identifying the clumps of dense gas in molecular clouds which give rise to these clusters before star formation significantly modifies their properties. Infrared dark clouds (IRDCs), dense regions seen in absorption against the diffuse infrared emission in the Galactic Plane, are amongst the best candidates for identifying such objects. In this talk I will discuss a recent new catalogue of IRDCs which has identified over 14,000 clouds. I will then explore some of the initial results on the properties of these clouds and the prospects for future work probing the structure of these clouds and the extremely young stars forming within them.