Our first glance
What you're seeing here is a five week-old embryo floating around in his/her "gestational sac" (the black area). (Note - five weeks one day is the gestational age, seven weeks one day in pregnancy terms.)
One centimetre long, but already with a little heartbeat that flickers on-screen - 123 beats a minute! We even got to hear it - thump-thump-thump. In addition to a heart, this embryo is already developing facial features, some limb buds and some primitive internal organs. But it still looks pretty extraterrestrial.