voyages? as in any expidition?
first trans atlantic flight
first flight around the moon (its awesome that we landed on it, but just the fact that they saw the shaded part and were able to get that far out changed everything)
Darwin and the RMS Beagle
magellan around the world
Are you allowed to think outside the box? In which case I say the Odessy. It was one of the earliest extensive pieces of western literature, has so many references in modern culture and every person I know of has studied it in school to some degree. It is probably one of the most famous stories ever told.
flight of the enola gay - dropped the bomb on Hiroshima and ended ww2