The Enᑯ

All places of "The End" were the levels where the civilizations can't ascend anymore. Meanwhile in a future, there will be two ways to continue:


 * Discover hypothetical technologies for colonizing the higher level, until you find most of them.
 * This pushes the capability limits of your colonization into further objects, allowing your civilization alone to go beyond.
 * This only works if we could discover solutions by hypothetical objects and technologies.
 * Or interact with creatures from a neighborhood civilization at your current level or higher.
 * However, this is really dangerous than the first way because the barriers to learn the language from themselves are really tedious.

Although those places are extremely difficult, even doable technologies by ours, they are the stopping points for civilizations until far future.

Examples
Our infamous example is the Local Group. The expansion of space is so fast that our neighborhood galaxies are pulling away from us by dark energy, a hypothetical object that goes faster than light. With everything we discovered in our universe, nobody can make a spaceship that can handle speeds faster than that. However, it may be possible to use a wormhole to move from one part of the universe to another quicker than light without having to accelerate quicker than light.