Begun during the Civil War, the transcontinental railroad employed 20,000 men, mostly immigrants, who built the iron road with their bare hands.
Postwar New York City and the global economic order told through the story of the World Trade Center.
The Pennsylvania Railroad Company accomplished an enormous engineering feat, but destroyed a great architectural monument.
Brothers Wilbur and Orville Wright built a flying machine that made its first flight in Kitty Hawk, North Carolina in 1903.
After 18 years of struggles, the Golden Gate Bridge opened on May 27, 1937.
The worst epidemic in American history killed over 600,000 Americans during World War I.
In 1934, American polar explorer Richard Byrd became the first to experience winter in Antarctica's interior.
"The Wizard of Menlo Park," Inventor Thomas Edison, built the first practical light bulb and revolutionized the world.