21.  It was the fourth military plane brought down by the rebels this year.

22.  The fourth hijacked plane, believed to be headed to Washington, crashed in rural Pennsylvania near Pittsburgh, possibly after passengers interfered with the hijackers.

23.  The fourth plane crashed in a Pennsylvania field.

24.  The fourth plane to be hit in six days, it caused the United Nations to suspend both humanitarian and operational flights.

25.  The fourth plane crashed into a field in Pennsylvania.

26.  The fourth plane crashed into the Pennsylvania countryside during an apparent struggle in the cockpit.

27.  A fourth plane crashed in Pennsylvania after passengers rebelled against their captors.

28.  A fourth plane crashed into a field in the eastern state of Pennsylvania after passengers apparently overpowered the hijackers.

29.  A fourth plane crashed in Pensylvania, with some reports saying it was headed for the White House.

30.  Similar ceremonies took place at the Pentagon, in New York, in Pennsylvania where the fourth hijacked plane crashed, and in towns and cities across the nation.