Crane crushes roof while lifting pool

This crane driver clearly didn't check the weight of the pool he was lifting over a house in the U.S. Part way through the video he nearly clips the chimney, which is bad enough, he should be nowhere near it. But as he extends the crane arm to position the pool before lowering, the weight overcomes the crame which tips forward and crushes the roof of the house.

The driver is upset mainly because he doesn't understand how it happened. We think he needs a few lessons on how this whole heavy object and gravity thing works.