On September 11, 2001, Al-Qaeda terrorists hijacked American Airlines Flight 11 and crashed it into the 1 WTC, striking between the 93rd and 99th floors, killing 1,344 people. Seventeen minutes later, a second group crashed the hijacked United Airlines Flight 175 into the WTC, striking between the 77th and 85th floors, fewer than 700 were killed. At 5:20 p.m., 7 World Trade Center started to collapse with the crumble of the east penthouse. The Vista Hotel was destroyed during the collapse of the twin towers. The three remaining buildings in the WTC plaza were damaged by debris and later were demolished. Many conspiracy theories have appeared which say that certain people in the United States government knew about the attacks beforehand, or even made them happen.