With nearly 48 hours passed since Malaysia Airlines Flight 370 disappeared en route to Beijing, the Boeing 777 has yet to be discovered. As investigators from numerous countries work to piece together what happened, here is everything we still do not know.

Friday afternoon, at about 1:40 pm EST, a passenger jet flying from Kuala Lumpur to Beijing disappeared from radar screens and lost radio contact with air traffic control. Malaysia Airlines Flight 370, which was scheduled to land four hours later, was carrying 227 passengers, including two infants, and 12 crew members.