On March 3, 1943, tragedy struck in London, at the Bethnal Green Tube station. People on their way down to the station to seek shelter from a air raid were caught in a crush when one person fell. Fifteen seconds later, 173 people were dead. The Stairway to Heaven is the Bethnal Green memorial, where the victims are remembered. But the ghosts of this tragedy do their own remembering late at night, when the trains fall silent. Join me for a walk around this touching monument.