The LIGO—Virgo Collaboration has now announced 50 confident detections of gravitational waves from compact object mergers. These novel observations encode important information about their progenitor stellar systems, such as the types of galactic environments they were born in, the intricacies of stellar evolution that persisted throughout their lives, and the physics of the supernovae that marked their deaths. In this talk, I will discuss important clues that particular gravitational-wave events have provided to help understand veiled processes of massive-star binary evolution and formation environments of merging black holes. By considering the full population of gravitational-wave events, I will show how the current dataset hints at a combination of astrophysical formation channels contributing to the detected population. Lastly, I will highlight the implications of observing gravitational-wave events with distinguishing characteristics, such as orbital eccentricity, and how such characteristics will be key in determining the dominant formation channel(s) of merging black holes.