Abstract: Understanding the origin of the proton mass has been identified as one of the most important questions to be addressed at the future Electron-Ion Collider (EIC).  In this talk, I first present a novel QCD analysis of the trace anomaly and its implications on the hadron mass structure.  I then discuss how one can access the trace anomaly contribution to the proton mass in near-threshold photo-production of J/psi and Upsilon at current and future experimental facilities.