The SARS CoV-2 spike glycoprotein harbors a furin cleavage site at the boundary between the S1/S2 subunits, which is processed during biogenesis and sets this virus apart from SARS-CoV and SARS-related CoVs. Cryo-EM structures of the SARS-CoV-2 spike ectodomain trimer providing a blueprint for the design of vaccines and inhibitors of viral entry. SARS-CoV spike murine polyclonal antibodies potentially inhibited SARS-CoV spike mediated entry into cells, indicating that cross-neutralizing antibodies targeting conserved spike epitopes can be elicited upon vaccination.