The first around-the-world air race was sponsored to prove that the airplane had a commercial future. Four pilots took off from Seattle and two returned 175 days later.
In 1934, American polar explorer Richard Byrd became the first to experience winter in Antarctica's interior.
During the Great Depression, Americans built the Hoover Dam, one of the greatest engineering works in history.
The effort of pioneering researchers to conceive babies through in vitro fertilization.
Major Walter Reed's discovery in 1900 that mosquitoes spread yellow fever halted an outbreak and led to the disease's eventual eradication.
The historic journey of Apollo 8 captivated the world in 1968 -- a bright spot in a year marked by political assassinations, race riots, and the Vietnam War.
Equipment failure, human error and bad luck led to the country's worst nuclear accident in 1979.
The contradictory history of a dam that became a statement of American power and prestige.
Robert Moses fueled some of the most ambitious -- and controversial -- public works projects ever conceived.