Such a great visualisation, found over at Wikipedia whilst researching a new Linux distribution of choice for a ThinkPad. Amazing that Slackware was first built in 1993 and is still being maintained.
Click to enlarge or head over to GNU/Linux Distribution Timeline to check out the original in various forms. GLDT is a cladogram of GNU/Linux distributions, placed on a timeline. The project started in 2006 and currently lists more than 450 distributions.
What's a cladogram? I hear you cry. Well, off the top of my head (ahem), it's a diagram that demonstrates relations among organisms, but one that does not show ancestor/descendant relationships or their evolution. Bring on the branches!