AP
The Twin Towers in 1999; and One World Trade Center in 2018.
The September 11th attacks took the lives of more than 3,000 Americans, and transformed the US in countless ways.
It sparked the Global War on Terror (which the US is now fighting in 76 countries), and the invasions of Afghanistan and Iraq.
It led to the creation of the Department of Homeland Security, the US Immigration and Customs Enforcement, and the Patriot Act.
And it also fundamentally changed New York City.
In honor of the 17th anniversary of the horrific attacks, we compiled 17 photos showing how Manhattan's Financial District and skyline have changed since 9/11 as the city rebuilt Ground Zero. See for yourself: