Large mergers, once rare, are becoming more common and costing jobs.

It was once rare for aid groups to become specific targets of war.

They were once rare but the number of these games is increasing.

How a once rare musical adventure sank to commonplace stock stuff is another story.

It was once rare to name a tournament after a living player.

Indeed, the sight of top executives facing criminal charges, once rare, has become almost common in recent months.

The once rare phenomenon of having a country hit cross over to pop success became more common.

Experts estimate that kidnappings in Mexico, once rare, now number at least 1,500 a year.

The woods and field surrounding the lake are the home of the once rare bluebird.