Photos show how Manhattan's skyline has changed since the 9/11 attacks

• This year marks the 24th anniversary of the 9/11 attacks. • The World Trade Center site has become a memorial to the 2,977 lives lost. • Photos show how New York City rebuilt ground zero.

Each September, two large beams of light reach into the night sky above Manhattan's Financial District in powerful tribute to the towers that once defined the city's skyline.

Thursday, September 11, marks 24 years since terrorists hijacked four commercial passenger planes, crashing two into New York's Twin Towers and forever changing the city. Another plane hit the Pentagon in Arlington County, Virginia, and the fourth crashed into a field in Shanksville, Pennsylvania, after passengers overpowered the hijackers.

In total, 2,977 victims lost their lives and, more than two decades later, their love