By Yuan Zhou

T he shocking disappearance of Malaysia Airlines Flight MH370 has captured the attention of millions around the world as the search for the airplane and its passengers and crew continues.What happened to the flight’s 239 passengers and crew after the plane left Kuala Lumpur on Saturday?It is becoming an increasingly desperate question as the days pass.

But it’s hardly the first mystery of its kind.Here are some half-solved and unsolved airline mysteries that kept investigators clueless for years.

Air France Flight 447:An Airbus A330 flight from Rio de Janeiro to Paris dived into the Atlantic Ocean in 2009,killing all 228 passengers and crew on board.But it took a full five days for search and rescue teams to find the wreck （殘骸 ）and another three years for investigators to report that ice crystals had caused the autopilot to disconnect.The bodies of 74 passengers remain unrecovered.

Amelia Earhart:Ace(王牌)pilot Amelia Earhart disappeared in her twin-engine monoplane Electra over the Pacific Ocean in 1937 in an attempt to circumnavigate the globe.No trace of her plane was ever found even after a multi-million dollar search effort,and Earhart was officially declared dead in 1939.

Flying Tiger Line Flight 739:a U.S.military flight left Guam in 1962 with more 90 personnel headed for the Philippines,but it never arrived.The pilots never issued a distress call,and 1,300 people involved in the U.S.military search never found any trace of wreckage.

British South American Airways:It took more than 50 years to find any trace of the 11 people aboard a 1947 flight that disappeared in the Andes Mountains.A pair of Argentineans rock climbers discovered engine wreckage in the Andes in 1998,and an army expedition later found human remains as well.

Uruguayan Air Force Flight 571:A flight headed to Santiago,Chile carrying 45 passengers and crew crashed into the Andes Mountains in poor weather in 1972,killing twelve people.In the meantime,eight were killed in an avalanche(雪崩)that hit the plane’s wreckage where they were taking shelter,and the rest stayed alive by eating the flesh of the dead before they were finally found more than two months after disappearing out of the sky.