Water over the dam is an expression about a past event.

VOA: special.2009.05.10

Clinton's comments at a joint press event with the Uruguayan leader were the highest-level expression of U.S.concern thus far about a Venezuelan arms buildup that gained momentum with an announcement this week that the South American state will buy Russian battle tanks and anti-aircraft missiles.

VOA: standard.2009.09.15

More than a social event, the carnival is an expression of belonging to a city, a social group and a nation.

UNESCO: Culture

For those of you who are unfamiliar with the term, it derives from an expression that was popular amongst medieval Londoners that referred to an event whose occurrence was believed to be impossible.

FORBES: Bevy of Black Swans Or Just A Flock of Seagulls?

Panelists at the event centered their main discussion points on the issues and challenges pertaining to freedom of expression and press freedom in Pakistan.

UNESCO: COMMUNICATION & INFORMATION