Babylon 5 is the name of a particular place where our story takes place.
It is numbered 5 because 1 through 3 were sabotaged/destroyed, and 4
mysteriously vanished within days of becoming operational. No one knows what
happened to it. All of which makes those involved with #5 just a trifle
uneasy.
jms
P.S. It might be useful if one of the sysops could move the initial
announcement message (or, rather, copy it) here for archival purposes.