Collapse of the World Trade Center
The World Trade Center, in Lower Manhattan, New York City, was destroyed after a series of terrorist attacks on September 11, 2001, killing almost 3,000 people at the site. Two commercial airliners hijacked by al-Qaeda members were deliberately flown into the complex's Twin Towers, at the time among the five tallest buildings in the world.
Source: Wikipedia — Collapse of the World Trade Center (CC BY-SA 4.0)