There are events in everyone's life that leave a lasting impression. The U.S. Postal Service recently asked the public to help them identify some of those events, people, trends and achievements of the twentieth century.

The 747 made the list -- chosen as one of the most significant technological achievements of the century.

On Nov. 15, the world's largest stamp, commemorating the achievements of the 747 -- the world's largest commercial airplane -- was unveiled at the Boeing Everett, Wash. factory -- the world's largest building. Only two other aviation achievements received stamps as part of the Postal Service's "Celebrate The Century" program -- the Wright brothers' first flight in 1903 and Charles Lindbergh's crossing of the Atlantic in 1927.

The Boeing 747-400 still looks like the first Boeing 747-100, with its big, graceful lines and the characteristic hump. But the modern 747-400 is, in other ways, an entirely different airplane from the 747-100. After all, a product that has accumulated 20 billion miles of airborne experience, in an industry that has changed profoundly, is bound to evolve technically.

Boeing has built 15 different 747 models over the years, and has delivered more than 1,230 in all -- clearly demonstrating the airplane's versatility, popularity, longevity and value.