On July 17, 1996, TWA Flight 800 took off from JFK Airport headed for Paris. Just 12 minutes later, it exploded over the shores of Long Island, New York. There were 230 people on board, and no one survived. Many eyewitnesses described seeing something heading toward the plane before it exploded, and the suspicion of terrorism was almost instant. The biggest investigation in aviation history, at that time, ensued. The government spent four years and millions of dollars in that investigation and 18 years later, many still question whether they got it right. A full four years after the crash of TWA Flight 800, the NTSB released its official report: It found the probable cause of the accident was a spark in the center fuel tank that eventually led to the explosion that brought down the aircraft. While they offered their best theory on where the spark came from, they never found a definitive answer.