Babylon 5 (1994-99)
The J. Michael Straczynski space opera is the imagining of the last of the Babylon Space stations where aliens tried to sort out their differences after a great war. It ran for 5 seasons between 1994 and 1999. WB has a couple dozen episodes. Strazinski said “”always been conceived as, fundamentally, a five year story, a novel for television”. I think that was a little bit of a change in the way science fiction on television was scripted. TV before this had science fiction series that were a lot less linear.