It's 40 years since the death of Yury Gagarin – the first man in space and the first man to orbit the earth. Even after all these years, mystery still surrounds his death in a plane crash, including some wild claims of alien abduction.

Gagarin was loved in Russia, with his warm smile endearing him to millions. He was a legend and world icon – not only a space hero, but a man with great charisma and a Hollywood smile.

His shocking death at just 34 remains a mystery 40 years on. He and his flight instructor Seryogin were on a routine training flight on a Mig-15 jet outside of Moscow.

There are dozens of theories for the crash: from alien abduction to orders of then-Soviet leader Leonid Brezhnev who allegedly felt threatened by Gagarin's popularity. Others suggested it was a collision with a weather balloon, or strong winds from a plane which flew near-by, or malfunctioning equipment.
 
James Oberg, who spent decades researching Soviet space programmes, says people don't want to accept the fact that the death was an accident.

“It helps people to accept his death, if he was a victim to a vast army of evil. If he was simply careless, or his instructor pilot was careless, if there was a poor combination of circumstances that's too trivial,” he believes.
 
A brief official investigation into the death said a manoeuvre sent the plane into a nosedive.

But it didn't explain exactly what happened and why.
 
The accident took place in the Novosyolovo village in Russia's Vladimir region. There is now a memorial in memory of Gagarin and his instructor. The centrepiece of it is 16 metres high – that's how high the flames were when the plane crashed in the woods.
 
Tens of thousands of people come to the memorial every year, a lot of them foreigners.

Meanwhile, the years gone by haven't affected Gagarin’s popularity for all Russians. It survived years of political turmoil, including the collapse of the Soviet Union.