I have to admit they've built up a powerful civilization.

Spain had to fight against the relatively powerful civilizations of the New World.

They're the most powerful civilization in our part of the galaxy, except for the Federation.

As of 2008, three stories force the Culture to consider its approach to more powerful civilizations.

A powerful civilization whom we refer to as Elders.

Still, we hesitated to contact so powerful a civilization.

But it would be a lot better if they could find a large and powerful civilization, one with plenty of military resources, like the Graks.

"Such powerful, advanced civilizations could exist today," the narrator says, "but so far we have no evidence of it."

Of the creatures who had built this powerful civilization, not a clue.

When such powerful civilizations clashed, everything was placed in jeopardy.