I just turned on the channel, in time to find that the race stewards have red flagged the course. They raced for 30 minutes -- and the replays I saw sure looked cool.

Here is the situation that caused the red flag:
FIA confirm concrete frame on manhole cover is the issue

As we mentioned earlier, the FIA have now confirmed is the framing around the manhole cover.

They have said: "Following inspection, it was the concrete frame around a manhole cover that has failed. We now need to check all of the other manhole covers which will take some time.

"We will be discussing with the local circuit engineering team about the length of time it will take to resolve and will update with any resultant changes to the schedule."
A big bummer.

Mark