Viruses developed various strategies to remodel infected cells to carry out genome replication and generate new progeny. While positive single-stranded RNA viruses hijack membranous organelles to form replication vesicles, many negative single-stranded RNA viruses use liquid organelles as a site of viral genome replication. We apply cellular cryo-electron tomography and correlative light and electron microscopy to study the replication and assembly of SARS-CoV-2 and Ebola viruses. We show that SARS-CoV-2 nsp3-4 are minimal components of the pore spanning double-membrane vesicles. In addition, we revealed Ebola virus nucleocapsid assembly inside membrane-less inclusion bodies using subtomogram averaging