Mass Disappearances
Approximately 600,000 missing person cases are filed in the United States annually per NamUS. Many of these cases or solved or "cancelled" per the FBI.
People may disappear for a number of reasons: physical danger, drug or alcohol use, environmental/weather factors, foul play, disasters, enforced disappearances, mental health conditions, or for unknown reasons.
Amnesty International indicates that this is a significant global problem.
Thousands remain missing.