In 1853, Elisha Otis demonstrated his "safety brake" which enabled the widespread deployment of safe passenger elevators. The proliferation of the passenger elevator changed the nature of building construction and the vertical growth of cities.
How would the world have been different in a "flatter" configuration that would have been the result of no passenger elevators?
"American Idol" is one of the highest-rated television series of all time and has launched the careers of literally dozens of music artists and bonafide stars.
How would American popular music, television, and culture be different today if it had never aired for its first season in the summer of 2002?
In the Compromise of 1790, the United States capital was fixed at the location we still know today, Washington, DC.
What if the capital had remained in New York City or had been moved later in time to a more central location?
