A sixteen-year-old boy was seriously injured on Saturday night when he entered a construction site and fell two storeys, the police said.
The accident happened in Ball Street, Paceville, at 11.30pm.
He was assisted by rescuers of the Civil Protection Department and an ambulance crew before being hospitalised in serious condition.
The police are investigating.
The accident is the second of its type in as many months.
On June 17 a 20-year-old French woman was seriously injured when she also entered a construction site in Paceville shortly after midnight and fell down a shaft.
She fell a height of one-and-a-half storeys.
She was rescued by members of the Civil Protection Department and hospitalised in grievous condition.