Biomolecular condensates, which assemble in cells to regulate key biological processes, are challenging to study due to their inherently dynamic nature. In this talk, we will present our integrative multi-scale approach, which integrates light microscopy, electron cryomicroscopy, cryotomography, and coarse-grained simulations. Together, these methods reveal new insights into the molecular organization and biogenesis of a model RNA polymerase II condensate, shedding light on its structural complexity.