The tale of the Tower of Babel, from Genesis 11: 1-9, is an "explanation"
of why there are so many different languages. You can find the story in some
of those languages by following the links below. Having a single text in a
variety of languages is a good way to see similarities and differences
between those languages.
The Tower of Babel did in fact exist: it was a seven-stage ziggurat
(stepped pyramid) with a temple to the god Marduk at the top. It was
called Etemenanki, or 'the temple of the platform between
heaven and earth', and was built in the city of Babylon sometime
during the 6th or 7th century BC.