Abstract
The H I Southern Galactic Plane Survey (SGPS) is an ideal dataset with which to explore the impact of massive stars on the Galactic ISM. We are using the SGPS to study the global properties of H I shells over size scales ranging from tens of parsecs to kiloparsecs. Here we present an intriguing Galactic chimney and discuss the Galactic distribution of large H I shells with respect to Galactic radius and spiral arms.
