Batallion 1 Chief: “Command post, Tower 1, all units. Evacuate the building. Command post, to all units.” — FDNY Battalion 1 Chief Joseph Pfeifer

KC: There’s smoke really bad.

911: Sit tight and we’ll get to you as soon as we can.

KC: I know you’ve got a lot in the building but we’re up on the top. Smoke rises too. Come on, I can barely breathe now – can’t see. It’s really bad, it’s black, it’s arid. We’re young men, not ready to die.

911: Hello?

KC: Hello… there’s three of us, two broken windows… Oh God! Oh…

— Kevin Cosgrove, cell phone conversation from South Tower,  World Trade Center

“You ready? OK. Let’s roll.” — Todd Beamer, Passenger on United Airlines Flight 93

“…it felt, just a few moments ago, like there was an explosion of some kind here at the Pentagon.” — NBC News Pentagon correspondent Jim Miklaszewski

“Ladies and gentlemen here… is the captain please sit down… Keep remaining sitting. We have a bomb on board. So sit.” — Transmission from United Airlines Flight 93

“Two airplanes… have crashed… into the World Trade Center… in an apparent terrorist attack on our country,” — President George W. Bush

“”Hey, get out of here” — Pilot of United Airlines Flight 93

“Beware any cockpit intrusion—Two a/c [aircraft] hit World Trade Center.” — United Airlines flight dispatcher Ed Ballinger, in a text message to all of his flights

“Give me a first-tier ground stop!” — FAA Manager Ben Sliney. This order closes all airspace within the authority of New York Center

“A second plane has hit the second tower. America is under attack.” — White House Chief of Staff Andrew Card to President George W. Bush