There has been a at a massive fire at the Notre Dame de Paris :

A fire that devastated Notre Dame Cathedral in the heart of Paris was brought under control by firefighters in the early hours of Tuesday morning, though officials warned there were still residual fires to put out.
Thousands of Parisians watched in horror from behind police cordons as a ferocious blaze devastated Notre Dame Cathedral on Monday night, destroying its spire and a large part of the roof.

An investigation has been opened by the prosecutor’s office, but police said it began accidentally and may be linked to building work at the cathedral. The 850-year-old gothic masterpiece had been undergoing restoration work.

The French president, Emmanuel Macron, attended the scene and later gave a speech in which he vowed that the cathedral would be rebuilt, as fire crews said the landmark’s rectangular bell towers and structure of the building had been saved.

I’m not sure how much has been lost, but given that the structure, the part that isn’t wood, is limestone and old mortar, which is very susceptible to fire damage.

I’m not sure what has been lost, but I’m pretty sure that when a final inventory is made there will be some very sad architects, artists, and historians.

In bizarrely related news, there has been a (relatively minor) fire at the al Aqsa mosque in Jerusalem.

Unlike the Notre Dame fire, the source of this one is currently suspicious, having occurred during a 15 minute change-over of local security:

A fire broke out in al-Aqsa mosque in Jerusalem, the third-holiest site in Islam, on Monday. The blaze didn’t cause significant damage, but it did endanger a part of the worship site that’s over 2,000 years old.

​The fire broke out in the guard room outside the al-Marwani Prayer Room Monday evening, according to a statement by the mosque’s Islamic Waqf (Endowments) Department. According to The New Arab, a guard reported a short gap in guard rotations between 7:15 and 7:30 p.m. local time.

Weird.