We are on the precipice of the Big Data gravitational-wave era. Pairs of stellar-mass black holes and neutron stars across our vast universe occasionally merge, unleashing bursts of gravitational waves that can now be detected here on Earth. Over the next few years, the population of detected mergers will rapidly increase from about a hundred today to millions of detections per year as new observing runs and next-generation detectors provide data with ever-increasing precision and to larger distances, pushing the reach of gravitational-wave astronomy to the edge of the observable universe! Most excitingly, this wealth of data will provide an unprecedented probe of the physics of black holes and neutron stars, and of the evolution of the binary massive stars that once formed them. This could open the new frontier of ‘gravitational-wave paleontology’: studying massive stars and binary evolution from their ‘remnant’ compact object mergers, with the goal of answering some of the biggest open questions in astrophysics today: How do these gravitational-wave sources form? What can we learn from them about the formation, lives, and explosive deaths of massive stars across cosmic time?  How do these sources help to enrich the universe with heavy metals? In this talk, I will outline the main bottleneck in this field: the “Progenitor Uncertainty Challenge”. I will discuss how my research group is leading efforts to identify, quantify, and eventually overcome this challenge with the aim to open the new frontier of gravitational-wave paleontology and make unprecedented discoveries about massive stars across cosmic time from gravitational waves, as well as from other upcoming multi-wavelength and multi-messenger observations. Those unable to attend the colloquium in person are invited to participate online through Zoom (Meeting ID: 942 0262 2849, passcode 792771) using the link: https://eu02web.zoom-x.de/j/94202622849?pwd=dGlPQXBiUytzY1M2UE5oUDRhbzNOZz09 During her visit to Heidelberg, Dr Broekgaarden will be available for meetings by arrangement with her host, Michela Mapelli (mapelli@uni-heidelberg.de)