History.com: What Happened to Twa Flight 800?

Minutes after its take off from New York's Kennedy International Airport, a Boeing 747 headed for Paris exploded midair over the Atlantic Ocean off the coast of Long Island on July 17, 1996, leaving all 230 people aboard dead. The four-year investigation into what caused the crash of Trans World Airlines Flight 800 was the longest, and at $40 million, the priciest in the history of the National Transportation Safety Board. Although the source that led to the explosion was never discovered, the investigation concluded the crash's cause was not a terrorist attack, but an electrical failure that ignited a nearly empty center wing fuel tank in the 25-year-old aircraft. The event remains one of the deadliest plane crashes in U.S. history.