This video shows an Apache Helicopter coming in for a landing. It appears the pilot was trying to land by bringing the chopper around the landing area first (possibly trying to show off?). To me, it looks like the pilot came in to low, and couldn’t get enough lift due to the altitude and lack of air pressure. He pulls up, missing the building by inches,then stalls and comes back around hitting the ground. The pilot lost trail rotor control and crashed. That is what appears to me happened.