The as-yet-undefined "dark space between galaxies" in the Babylon 5 universe.
What the First Ones left for millions of years ago-Following this first pilgrimage, only the Shadows and Vorlons had been known to remain in our galaxy, though scattered others from various races had also been left behind.
All of these remaining First Ones left with the eldest First One, Lorien, in the Earth year 2261, at last leaving our galaxy in the hands of the younger races.