Which Apollo mission was the first one to land on the Moon?

The story behind the answer

Apollo 11 was the first crewed mission to land on the Moon, touching down in the Sea of Tranquility on July 20, 1969. Neil Armstrong and Buzz Aldrin walked on the surface while Michael Collins orbited above. Armstrong’s “one small step” quote became an icon of the space age.

The other options didn’t land: Apollo 9 tested the Lunar Module in Earth orbit; Apollo 10 was a “dress rehearsal” that approached the surface but didn’t land; Apollo 13 suffered an explosion and aborted the landing. Memory tip: “Apollo 10 rehearses, 11 performs”—and think “11 = one-one,” the first “one” to set foot on the Moon.