It is partly thanks to an accidental collision over 50 years ago that the new twin towers were built so tough. Engineering to incorporate lessons from the past helped the towers continue standing for an hour and more before collapsing. This saved thousands and thousands of lives in the World Trade Center disaster.

This excerpt tells the story of the earlier collision. It was a shocking and terrible accident at the time, which looks very small from our perspective today. — Editor

Collision with a New York Skyscraper

Jack Wernli, a staff photographer who snapped celebrities on the observation deck of the Empire State Building, was late again for work on the morning of Saturday, July 28, 1945. He got off the elevator on the 85th floor and tiptoed up the stairs to 86, intent on avoiding his boss. At 9:49 A.M., as he pulled the lever on the time clock, there was a deafening explosion. He figured his boss had rigged a booby trap.

Army Lieutenant Colonel William Smith Jr., a 27-year-old veteran of 34 bombing missions over Germany, had been flying a twin-engine B-25 bomber from Bedford, Massachusetts, to New York's LaGuardia Airport, and had secured permission to continue to Newark, New Jersey.

This article is excerpted from Empire: A Tale of Obsession, Betrayal, and the Battle for an American Icon by Mitchell Pacelle, with permission of the publisher, John Wiley & Sons.