1900s: In 1903, the Wright Brothers embark on the first flights ever in recorded history.

Today: "It's time to say goodbye, station, and good luck, new crew," says the outgoing station commander of the spacecraft Discovery, Russian Astronaut Yury Usachev, as he prepares to return to Earth.

1900s: In 1905, Sigmund Freud coins the term "psychoanalysis," defined as self-examination into one's inner thoughts and feelings.

Today: Internet service providers offer customers the opportunity to discuss their personal problems or field questions to experts in the field of psychology online.

1900s: In 1907, Albert Einstein expresses the relation between matter and energy in the formula e=mc2.

Today: Wolfgang Ketterle earns a Nobel Prize after demonstrating the first "atom laser" by producing a steady stream of drops of identical atoms from a sodium atom condensate.

1900s: In 1913, American geneticist A. H. Sturtevant develops gene mapping.

Today: After English...