A woman walks near a giant display with an image of a destroyed US aircraft B52 commemorating the 40th anniversary of the Linebacker 2 bombing campaign on a street in Hanoi, Dec 18, 2012. Vietnam marks the 40th anniversary of the Linebacker 2 campaign, also known as the "Christmas Bombing", the last airstrike operated by the US military between Dec 18 and Dec 30, 1972, during which Vietnam said thousands of residents were killed and 81 US aircraft shot down, 34 of them B52 planes.