What did the court decide in Bell Atlantic Corp. v. Twombly?
Answered for: US
Factual allegations must be enough to raise a right to relief above the speculative level
The Court replaced Conley's 'no set of facts' language with a plausibility requirement for federal complaints. The sentence above is the court in its own words.
This answer is true in US and nowhere else on this site. Another jurisdiction is another answer, or an honest gap: see what has been read for US.