This talk will summarize the recent high-resolution data of RNA Polymerase II from cryo-EM which revolutionized our understanding of eukaryotic transcription. doc. Štefl will discuss also the recent low-resolution images of transcription machinery which show that RNA polymerase II and its associated factors employ phase separation to form dynamic membrane-less organelles. These organelles function as condensed phase microreactors to increase local concentration of multiple interaction/reaction components that accelerates biochemical reactions or sequester molecules.