Apollo 11 Spaceflight, First Manned Moon Landing

Charles Duke, acting as CAPCOM during the landing phase, acknowledged their landing by saying "We copy you down, Eagle".
Armstrong continued with the remainder of the post landing checklist, "Engine arm is off." before responding to Duke with the words, "Houston, Tranquility Base here. The Eagle has landed." Armstrong's abrupt change of call sign from "Eagle" to "Tranquility Base" caused momentary confusion at Mission Control and Duke remained silent for a couple of seconds before expressing the relief of Mission Control: "Roger, Twan-- Tranquility, we copy you on the ground. You got a bunch of guys about to turn blue. We're breathing again. Thanks a lot."
Two and a half hours after landing, before preparations began for the EVA, Aldrin broadcast that:
"This is the LM pilot. I'd like to take this opportunity to ask every person listening in, whoever and wherever they may be, to pause for a moment and contemplate the events of the past few hours and to give thanks in his or her own way."