Over four years since flight MH370 mysteriously went missing, people are still completely stumped as to what could have happened to the plane and its passengers.
The Boeing 777 disappeared without a trace in March 2014 when it was en route to Beijing, with 238 passengers on board.
A team of Malaysian investigators said that there was no reason to suspect a mechanical problem, and that there was nothing that had suggested any malicious intent, concluding: "The team is unable to determine the real cause for the disappearance of MH370."
Despite extensive search efforts over the years, wreckage of the plane has never been found - but that hasn't stopped countless people coming forward with new theories.
The latest comes from Philip Baum, editor of Aviation Security International and visiting professor of aviation security at Coventry University, who reckons that there could have been a stowaway on board.
"I think a stowaway is a strong possibility, especially as no officials seem to want to even contemplate the possibility," he told The Independent.
Baum speculates that someone could have got on board while the aircraft was still on the ground in Kuala Lumpur, before hiding in the underfloor avionics bay behind the flight deck - an area known as the E/E (electronics and engineering) bay.
Baum thinks that one or more individuals could have gained access from a 'hinged, self-closing access panel'.
His magazine, Aviation Security International, reports that 123 stowaway attempts have been reported internationally on 107 different flights.
Apparently many people conceal themselves within the wheel wells - running the risk of freezing to death or even falling when the undercarriage is deployed - while some others board planes disguised as staff like cleaners or airport officials.
While we still have no concrete understanding of what happened to MH370, in 2015 a wing flaperon washed ashore Reunion Island, off the coast of Africa - when investigators confirmed that the piece was almost certainly from the plane. Another similar piece was also found on the coast of Mozambique last year.
The Australian Commonwealth Scientific and Industrial Research Organisation created modelling based on how that flaperon made its way to the island and tried to calculate where the plane went down.
Australian Commonwealth Scientific and Industrial Research Organisation researchers then made replicas of the wing piece, and tested these to see how it would float depending on the ocean conditions.
Off the back of this, the organisation released a report that said: "This new information does not change our earlier estimate of the most probable location of the aircraft. It does, however, increase our confidence in that estimate, so we are now even more confident that the aircraft is within the new search.
"Our earlier report argued that it was where debris was not found that is the key to identifying a fairly precise location of the crash. This aspect of the earlier work is unchanged, other than being reinforced by also considering the trajectories of high-windage items that were probably also within the debris field.
"The only thing that our recent work changes is our confidence in the accuracy of the estimated location, which is within the new search area identified and recommended by the First Principles Review, and most likely at the southern end of that, near 35 degrees south."
Featured Image Credit: PA