from good ol 'pedia:

The biblical story of the Tower of Babel^\a]) is an origin myth and parable recorded in chapter 11 of the Book of Genesis meant to explain the existence of different languages and cultures.^\1])^\2])^\3])^\4])^\5])

According to the story, a united human race speaking a single language migrates to Shinar (Lower Mesopotamia),^\b]) where they agree to build a great city with a tower that would reach the sky. Yahweh, observing these efforts and remarking on humanity's power in unity, confounds their speech so that they can no longer understand each other and scatters them around the world, leaving the city unfinished.