The destruction of the Jews was an unprecedented occurrence, a primordial act that had not been imagined before it burst forth.

The destruction that such an unprecedented occurrence would wreak is incalculable.

The Arabs and their followers were thrown into a fine rage at this unprecedented occurrence.

No province or territory was denied a medal in the final standings, an unprecedented occurrence for the Canada Games.

Truly this is an unprecedented occurrence!

This is an unprecedented occurrence for Albert due to his unusual ditto-making prowess.

A record 34 different players win tournaments, and no-one is able to win more than twice, an unprecedented occurrence.

It was an unprecedented occurrence.

The unprecedented occurrence had me worried.

This is an unprecedented occurrence.