#4 Another 9/11
So it turns out that 9/11 was not the first such incident. The world has witnessed 9/11 decades before the current generation actually experienced it.
So it all happened on 28th July, 1945. On this day, a B-25 Mitchell Bomber that was on a routine personnel transport mission to Newark Airport from Bedford Army Air Field requested for clearance to land. William Franklin Smith, Jr. was the pilot and he was advised of zero visibility.
He still proceeded anyway and was soon disoriented because of the dense fog and instead of taking a left after crossing the Chrysler building, took a right.

#3 The Deadly Collision
On the same day at 9.40 am, the aircraft collided with the north side of the Empire State Building. It disrupted the area between floor number 78 and floor number 80. It left an 18x20ft hole in the building where National Catholic Welfare Council offices were located.
This incident was very intense. The engines flew here and there and before anyone could realise what happened, things got out of hand.
Checkout what happened with one of the engines ahead.

#2 That Massive Fire
The entire incident was so deadly that one of the engines went through the South side, opposite to the impact, and flew till the next block where it dropped 900 ft finally landing on the roof of a nearby building and ignited a fire that consumed a penthouse art studio.
Now this was about one engine. The other engine along with one of its part of the landing gear went down an elevator shaft. The incident resulted in the massive fire and till date is the only fire that erupted at such a height and was brought under control. Checkout the video of this incident ahead.

#1 The Video
14 people died in that incident. Betty Lou Oliver, elevator operator was injured and the rescue team decided to transport her using an elevator that featured weakened cables.
The elevator's cable broke and Betty survived a plunge of 75 storeys. This is still a world record. Checkout this nerve wrecking video below.