The sandwich graphic actually shows the CD upside down. The shiny side with the data bumps is normally the down side. The bumps are lined up in a long spiral track of data that starts from the center and works its way out. The spiral track is VERY long. In fact, it would stretch almost four miles if you were able to unwind it.
Spirals start from the inside and work outwards.
What the spiral graphic does not begin to show is how incredibly small the track is. The track is just 0.5 microns wide much thinner than a strand of hair. And there s only 1.6 microns between tracks. The data bumps are just as amazing. They're just 125 nanometers high, whis is MUCH smaller than the tiniest speck of dust.