Although the official NASA flight plan called for a crew rest period before extra-vehicular activity, Armstrong requested that the EVA be moved to earlier in the evening, Houston time. Once Armstrong and Aldrin were ready to go outside, Eagle was depressurized, the hatch was opened and Armstrong made his way down the ladder first.

At the bottom of the ladder, Armstrong said "I'm going to step off the LEM now". He then turned and set his left boot on the Moon surface at 2:56 UTC July 21, 1969, then pronounced his famous words "That's one small step for [a] man, one giant leap for mankind." More than half a billion people were watching this on television. It was the first human foot planted on "another world".

Now countries and organizations have long-term intentions to send humans to Mars. What do you know and think about that? Share our opinion on the comments below!