Anyhoo, I'm waffling, here's the story ~
'In broad daylight at twelve noon on June 7th, 1926, a schoolboy named Peter Kelly told a friend that he had just seen something terrifying staring at him from a window-pane in the Harrington School, which was situated in Liverpool Stanhope Street. Peter said he had almost fallen off his bicycle after seeing a grotesque skull gazing down at him from the school window overlooking Grafton Street. Peter's mate was naturally sceptical, and said, "Take me to the school then."
Peter let his friend sit on the back of the bike saddle and he rode off to the Harrington School. When the boys arrived, a young woman was standing there on the pavement, staring up the windows of the building with a look of excited expectation. She too had noticed the skull, which looked as if it was screaming. All around the disturbing apparition there were flames, which seemed to consume the grotesque face. At this point, the lady on the pavement screamed out and threw her hands to her face. Peter's mate just said, "Wow. Did you see that?"
"I told you, you doubting Thomas." said Peter.
The young lady ran home to tell her family of the strange vision and the tale spread like wildfire across the city. Within the hour, crowds were swarming around the railings of the Harrington School, eagerly waiting for the vision to reappear. The hordes of thrillseekers and curious bystanders were not disappointed. A pale ghostly face of an old woman materialised at an upper-floor window in the school, wringing her hands and shaking her head with a sorrowful expression. Several superstitious members of the crowd made the sign of the cross, and a couple fled from Stanhope Street in fear. A gang of men who had been demolishing a house down the road stopped work to see what was going on. They too saw a whole gallery of eerie faces appear in the five windows of the school. A man stared out with his hair on fire, shaking his head. His teeth were clenched and he seemed to be in terrible pain. Then the flames scorched his face and turned it black so that only his teeth and the white of his eyes could be seen. The other faces were of children, and they too were on fire. The flames quickly obscured the heads, and several members of the crowd either fainted or turned away in horror.
The fire brigade turned up, as people had assumed that there was a fire raging in the school. But there was no smoke coming from the building, and when the fire officers hammered on the school door, a care-taker answered. He was told about the fire report, but said he had just been around the building and that there certainly wasn't a flame to be seen anywhere. The fire officers went up to the floor where the distressed faces had stared out, and they saw that the classrooms there were deserted. When one fire officer came to the window, the crowds in Grafton Street and Stanhope street mistook him for another vision, and they cried out in fright. By now, the faces had disappeared.
The Liverpool Echo and several other newspapers reported the strange story and said it had all been a case of mass hysteria. The newspapers conjectured that the incident had all probably been caused by reflections in the school windows.
The old care-taker claimed he knew the real truth, but the journalists never bothered interviewing him. The care-taker knew that the glass panes the burning faces had peered through at the public had been salvaged from a house in Edge Hill over a year ago. That house had been destroyed in a blaze which claimed the lives of a large family. The firefighters had seen the victims of the blaze, who were young and old, screaming at the windows as the smoke overcame them and the flames roasted them alive. An unscrupulous glazier later took many of the the intact glass panes from the burnt-out shell of the house and used them when he was contracted to put new glass windows in the Harrington School. The janitor believed that the tragic faces of the blaze victims had somehow been absorbed into the window panes. The care-taker's theory was way ahead of its time; this was years before three-dimensional hologram images were stored on glass plates by a laser.
But it seems the Harrington School faces might have been a premonition, because one year later, almost to the day, the care-taker and his family were themselves burnt alive when a fire broke out in their home. Witnesses of the blaze said the care-taker appeared at the window, and seemed to be trying to open it, but the flames rose up and charred him. They burnt his hair, and within seconds his face had turned black with the smoke and fire. The care-taker, his four children and his old mother also died in the tragic blaze.'
Hammy x x x
, so maybe another urban myth. 
I could repeat an appalling joke to make up for any disappointment...or maybe not 
how can this explain several people seeing exactly the same thing ?