WASHINGTON D.C., June 29, 2016 (Xinhua) --A press preview for the re-opening of the "Boeing Milestones of Flight Hall" is held at the National Air and Space Museum in Washington D.C., the United States, on June 28, 2016. The National Air and Space Museum will reopen the "Boeing Milestones of Flight Hall" on July 1, coinciding with the museum's 40th anniversary. (Xinhua/Bao Dandan)
