Chandra High Energy Transmission Grating Spectrometer (HETGS) observations of the extremely luminous and violent X-ray binary Cir X-1 reveal many X-ray emission lines showing broad P Cygni profiles. These are from H-like and He-like ions of Ne, Mg, Si, S, Ar, and Fe. The lines originate in a high-velocity (up to 2000 km s) outflow, which may be an accretion disk wind. Cir X-1 has a radio jet, a...