Family members, guests and members of the group Friends of Flight 93 honor the memory of the 40 passengers and crew members of United Airlines Flight 93, who died on September 11, 2001, when hijackers crashed the plane in a field near Shanksville, Pennsylvania. Relatives place candles under the names of the crew members and passengers in front of the Wall of Names at the Flight 93 National Memorial on the eve of the 20th anniversary of the attacks. IMAGES