사고가 난

where an accident happened

→ 사고
phrase Rare #23,430
where an accident happened 난 means “happened” here. It usually modifies a noun, as in 사고가 난 곳, “the place where an accident happened.”
KO: 사고가 난 곳을 경찰에 알려 줬어요.
EN: I told the police where the accident happened.

사고가 난 거 예요?

Did an accident happen?

— 마농의 샘 1부 (1986)

바로 그때 사고가 난 거 예요

That was exactly when the accident happened.

— 세 가지 색: 블루 (1993)

사고가 난 곳은 칼리히야

The accident happened in Kalihiya.

— 더 레킹 크루 (2026)

여의도에서 누구를 만난다고 가다가 사고가 난 거 죠

You were on your way to meet someone in Yeouido when you got into an accident, right?

— Il Mare (2000)