On March 8, 2014, the Malaysian Airlines Flight MH370 took off from Kuala Lumpur with 239 people on board.
It should have landed in Beijing, China, later that day but instead disappeared less than an hour after take-off.
The wreckage of the Boeing 777 has never been found, nor has any trace of the passengers and cabin crew on board.
Debris began to wash up on beaches across the Indian Ocean more than three years after the plane vanished.
Heartbreakingly, the search for the missing jet was called off in 2018 - but there are still no answers as to what actually happened to Flight MH370.
Conspiracy theories surrounding the plane have circulated almost as soon as it went missing.
Did the pilot deliberately change the course in a gruesome murder suicide or was the plane hijacked?
Were its controls remotely hacked and was it landed safely outside of the radar that should have been tracking it.
MH370 set off in a normal take-off from Kuala Lumpur but 38 minutes into the flight it made its final communication with air traffic control.
It disappeared from conventional radar minutes later but was tracked by military systems for another hour, where it seemed to be deviating from its planned flight path.
Journalist Ean Higgins author of, The Hunt For MH370, believes he knows exactly what happened to the jet.
Amateur detective Mick Gilbert came up wth the theory, although there is no concrete evidence that this is wat happened.
He claims there was a devastating blaze in the plane's cockpit around 40 minutes into the flight when the windshield heater on the pilot's side caught fire.
Ean says this cold have burned out some circuits, including the secondary radar transponder and the communication systems.
Pilots are trained for emergencies just like this and would have simply put on their oxygen masks and cut the power to the heater.
But Ean claims this led to a catastrophic chain of events that caused the deaths of everyone on board.
By cutting power, the crew would also have switched off the satelite data unit, which meant they were no longer linked to satellites.
Ean then believes the First Officer Fariq Abdul Hamid, will have been the one in charge of the plane while Captain Zaharie Ahmad Shah dealt with the blaze.
As soon as the fire was under control the captain and first officer would have made a distress call.
Emergency training for pilots stressses that making sure the plane remains airborne and finding a course for the nearest airport are the two initial priorities in an in-flight emergency.
The third is to radio for help and to let air traffic control know what is happening, which means the plane could have changed route without anyone on the ground being aware.
However, Ean believes that during the crisis, one of the oxygen masks the two pilots were wearing was yanked out of its socket.
The cockpit would then have been filled with the contents of the oxygen bottle, which is a highly flammable gas, and could easily cause an explosion.
Captain Zaharie was already on his feet and trying to deal with the flames - but First Officer Fariq would have been incinerated as he tried to control the plane.
An explosion of this size would have weakened the windshield of the aircraft, which would in turn have caused a rapid decompression.
In this situatons, oxygen masks would fall from the overhead compartments, giving passengers 12 minutes of air in the out of control plane.
Ean then says Captain Zaharie could have fled the cockpit to reach an oxygen mask before he fell unconscious before making his way back into the front of the plane.
With the communication equipment destroyed in the explosion, the captain then had a truly horrifying decision to make.
He had just minutes of oxygen left and many of the passengers were dead or already in comas as their air supply ran out.
Captain Zaharie could either try to crash land over Penang, a heavily built up area, and possibly save himself and the flight attendant who had helped him back into the cockpit but at huge risk to the thousands of people on the ground.
Missing flight MH370
Or he could divert the aircraft over the Southern Indian Ocean and crash land in the sea.
It would mean everyone on board would perish but would save the lives of the innocent people on the land below.
While many have doubted this theory, one key element does give it some credibility.
When Captain Zaharie re-entered the cockpit it would have automatically switched the satellite communications system back on.
Mystery has surrounded why it was switched off and then back on again.