A Moscow metro train was transformed into a disastrous explosion waiting to happen by a pair of amateur scientists.
Two men have been arrested after attempting to create a super sensitive explosive - and then taking it on public transport to try it out in Bitssevsky Park in the south of Russia's capital.
The pair, postgraduate student Denis Gintovt, 27, and undergraduate Maxim Kosykh, 20, said that they hoped to win a big cash prize for the chemistry project after confessing to police that they had illegally manufactured explosives.
They told police they wanted to make a new explosive "for the advancement of science", but they admitted that they knew their risky research was illegal.
After setting up home labs, they made a substitute for TNT called Pentaeririta Tetranitrate and a powerful detonator called styphnic acid - creating a volatile cocktail which experts say could blow at any moment.
"If the liquid is poured into a drain it could explode due to the slightest movement of water in the pipes," a source close to the investigation told Life News. "If it is spilled on the ground, the vibrations of human footsteps could set it off."
So agreeing to meet at a metro station before testing their invention could have been catastrophic, experts said.
"An explosion could occur from any sudden braking on the train, or on a bus," the source added. "Such a blast could cause an incredible number of casualties."
The older man, Gintovt, had already come to the attention of the authorities after graduating in medical chemistry from a university in Novosibirsk. He was implicated in a gang making bombs in the Siberian city but evaded capture until he came to Moscow.
After their arrest the two students were found to be carrying explosives and detonators, with similar materials discovered in their flats.
Both have been charged with the illegal manufacture of explosives.