From Chapter 1 of K&R's The C Programming Language:
"The only way to learn a new programming language is by writing programs in it. The first program to write is the same for all languages:
Print the words
And with those words, written back in 1974, began forty years of tradition that's likely to stretch well into the future. One study has found 204 examples of Hello World.
A fitful greeting for man's first expression to the (through an) first artificially intelligent machine.