X-Men: Apocalypse Final Trailer - 10 Major Plots Hints

Here we get a shot of fire erupting out of the Cerebro room, which is pretty impressive itself, but then that fire spreads throughout the whole mansion as we get a couple of glimpses of Charles Xavier's School for Gifted Youngsters burning to the ground.

Given that we see the fire starting from Cerebro, we can piece together that with a shot from the previous trailer, which showed Havok unleashing his powers inside the room, that it's actually he who causes the fire at the school, albeit unintentionally.

Of course, there are a huge number of mutants in the mansion at the time, so we're also going to be seeing a number of characters caught in the fire, though whether or not any will die at this point is another matter (and a little unlikely).