Wikipedia surpassed its first significant content milestones in its earliest weeks online, an early sign of the free encyclopedia's rapid growth.

Hijackers flew American Airlines Flight 11 into the North Tower of the World Trade Center, the first of four coordinated al-Qaeda attacks that killed nearly 3,000 people.

Nineteen al-Qaeda hijackers crashed four airliners into the World Trade Center, the Pentagon, and a Pennsylvania field, killing nearly 3,000 people.

NASA's Deep Space 1 probe flew within 2,200 kilometers of comet Borrelly, capturing the sharpest images yet taken of a comet's nucleus.

American and British forces launched airstrikes against Taliban and al-Qaeda targets, opening the war that would become America's longest.

Apple's iPod launched publicly to modest fanfare, introducing a 5-gigabyte hard drive music player that would upend the recording and retail music industries.

American and British forces began Operation Enduring Freedom, striking Taliban and al-Qaeda targets across Afghanistan in response to the September 11 attacks.

Placeholder event removed for accuracy.

U.S. and Afghan forces launched a major assault on al-Qaeda positions in the Tora Bora mountains, hunting for Osama bin Laden.