HI supershells and chimneys play a pivotal, though not fully understood, role in the Galactic ecosystem. HI shells are typically detected as voids in the Galactic neutral hydrogen (HI) with walls of swept up emission. These objects heat and reshape the interstellar medium (ISM) on scales of hundreds of parsecs, making them a significant source of structure and energy input in the ISM. HI supershells also provide convenient locations for energy dissipation on small scales. For example, instabilities that develop along the dense swept-up walls may be sites of cooling and molecular cloud formation. Understanding this transition from the hot-ionized gas presumably filling the interior of shells, to the warm neutral medium of the outer walls, to the cold neutral medium along the small-scale instability created features, and finally to molecular gas is crucial to understanding the evolution of the ISM. Recent surveys, such as the Southern Galactic Plane Survey (SGPS), have reopened the field of HI shell and ISM physics, by providing images of large areas with high angular resolution. I will present HI data from the SGPS, with spatial dynamic range of 200 to 1, that allow us to resolve the majority of the ISM life-cycle in individual objects.