Paris faces hottest day ever, prompting concerns for Notre Dame Cathedral

Temperatures reached a sweltering 107 degrees Thursday.

PARIS -- Paris experienced its hottest day on record Thursday, as authorities warned the extreme heat could pose a threat to the rebuilding work at Notre Dame Cathedral.

The temperature rose to a sweltering 107 degrees at the peak of the heat in the afternoon. That means July 25, 2019, will go down in history as the hottest day the French capital ever recorded, smashing the previous record of 104.7 degrees set in 1947, according to Meteo-France, the national meteorological service.

Much of the city center, usually abuzz with tourists, remained empty as temperatures soared around mid-afternoon. Public health authorities have issued several warnings to stay away from the sun during the hottest parts of the day.

However, some Parisians and tourists have been enjoying the day by swimming in the fountains near the Eiffel Tower. The city council opened up town halls and government buildings to be used as air conditioned spaces for people to escape the heat, and a service has been provided to the elderly to drive them to the nearest cool-room at their request, according to local media.

As the heat wave spreads across the whole of Europe, Parisian authorities face a unique problem with regards to Notre Dame, the historic cathedral devastated by a fire in April.

"I am very worried about the heat wave," Philippe Villeneuve, the chief architect for the cathedral's restoration, told Reuters Wednesday. "What I fear is that the joints or the masonry, as they dry, lose their coherence, their cohesion and their structural qualities and that all of sudden, the vault gives way."

Villeneuve warned that the cathedral's vaulted ceiling "could well collapse," although the cathedral seems to have withstood the heat for the time being.