On January 8, 1902, a commuter train traveling through a tunnel in New York City's Grand Central Depot ran into another train, killing 17 people. An engineer's innovative response to the crisis gave birth to one of America's greatest establishments: Grand Central Terminal.

In 1910, the Pennsylvania Railroad successfully accomplished an enormous engineering feat: knitting together the entire eastern half of the United States by building tunnels under New York City's Hudson and East Rivers, connecting the railroad to New York and, eventually, to New England. The tunnels terminated in what was one of the greatest architectural achievements of its time, Pennsylvania Station. Designed by renowned architect Charles McKim, and inspired by the Roman baths of Caracalla, Pennsylvania Station covered nearly eight acres, extended two city blocks, and housed one of the largest public spaces in the world. But just 53 years after the station's opening, the unthinkable happened. What was supposed to herald and represent the American Empire was slated to be destroyed. The financially strapped Pennsylvania Railroad announced it would tear down what had once been its crowning jewel to build Madison Square Garden. It took three years to dismantle Alexander Cassatt's monumental station. In the wake of the destruction, New York City established the Landmarks Preservation Commission, sparing Grand Central Terminal a similar fate.

Meet Nikola Tesla, the genius engineer and tireless inventor whose technology revolutionized the electrical age of the 20th century. Although eclipsed in fame by Edison and Marconi, it was Tesla's vision that paved the way for today's wireless world. His fertile but undisciplined imagination was the source of his genius but also his downfall, as the image of Tesla as a mad scientist came to overshadow his reputation as a brilliant innovator.