A fire broke out at Notre Dame Cathedral in Paris, France, on Monday, 15 April, 2019.
5
Although the main reason for the fire was not officially announced at that time, authorities surmised that the ongoing renovations at the cathedral were the probable cause of the fire.
5
The renovations had been undertaken because of cracks in the cathedral.
4
Officials conducting an initial investigation into the cause of the fire believed that it was probably caused by an electrical problem or a cigarette not being properly extinguished.
6
A preliminary investigation into the situation was carried out on Wednesday, 17 April, but due to safety issues, it was not possible to carry out a detailed search on the partially burned interior of the cathedral.
3
After further investigation of cathedral staff and the workers who were repairing and renovating the cathedral at the time of the fire, officials concluded that the fire was an accident.
3
On 19 April, French officials released a report stating that investigators believed that it was mostly likely an electrical short circuit that had caused the fire.
3
The conical spire and roof were destroyed in the fire,.
2
and its main tower and walls were severely damaged.
6
Based on photos and videos collected as part of the investigation, the fire at the cathedral broke out in the central part of the roof next to the conical spire.
8
In addition, police studied the workings of fire safety sensors and the elevator, which was built by the employees working on the cathedral’s renovation.
8
In June 2019, French experts announced that, after extensive investigation, it was determined that the Notre Dame Cathedral fire was not intentional or criminal in any way, and that the probable cause was a half-extinguished cigarette or an electrical short circuit.
7
In April, a spokesman for the scaffolding company that was working on the cathedral renovations before the fire admitted that its employees sometimes smoked on the site; however he rejected the hypothesis that a cigarette butt could be the main cause of the fire.
7

Warning: these questons and answers are not all representative of the way questions will be asked and answered in the pilot, because some questions are compound and some answers do not include citations.

Q: When did a fire break out at Notre Dame Cathedral in Paris?
A: Monday, 15 April, 2019

Q: What did authorities initially surmise had caused the fire?
A: Ongoing renovations

Q: Why were renovations taking place at the Cathedral prior to the fire?
A: Cracks in the cathedral

Q: What did investigators conducting an initial investigation into the cause of the fire believe were two possible causes for the fire?
A: An electrical problem, or a cigarette not being properly extinguished

Q: What parts of the cathedral were destroyed in the fire?
A: The conical spire and roof

Q: What parts of the cathedral were severely damaged in the fire?
A: Its main tower and wallsA: What prevented a detailed search of the partially burned interior of the cathedral on 17 April?A: Safety issues

Q: Which people, who were in the cathedral at the time of the fire, did investigators question to conclude that the fire was an accident?
A: Cathedral staff and the workers renovating the cathedral

Q: Based on photographic and video evidence, where did investigators conclude that the fire had started?
A: The central part of the roof next to the conical spire

Q: What devices did police study that workers had installed at the cathedral as part of the renovations?
A: Fire safety sensors and elevator

Q: What did a spokesman for the scaffolding company working on the cathedral renovations before the fire admit about the company’s workers?
A: That they occasionally smoked on the worksite

Q: What hypothesis did the same spokesman reject as a main cause of the fire?
A: That a cigarette butt could be the main cause of the fire