King's Cross Fire (London's Subway Inferno)

On the night of 18 November 1987, a harmless match produced a small flame on the escalator at King's Cross tube station. Suddenly, the containable flame explodes rapidly into a fireball. It charges up the escalator and kills 31 people in the ticket hall 20m away. The inferno leaves investigators stumped. When the answer is revealed, it will shock everyone, adding a new chapter to the laws of fire dynamics.