The Ultimate Galaxy, officially Galaxy SGW-2249, was a Galaxy in the far reaches of space that was only accessible by a wormhole that opened up once every fourteen years.
History & Information
The gateway wormhole was only there for around 9.845 seconds, though, and it was practically impossible to find out exactly where the wormhole appeared. The Eloquian Alliance began a tracking project of the wormhole in 456 BBY, and the project ended in 19 BBY. They discovered several things, one was that the wormhole appeared about two billion kilometers away from its last known position, and was approximately 14.598 kilometers wide.
Snakro Intermutiverseal Parliamentary Republic Has already explored this galaxy, and has about 12,345,227,847,567 colonies there.