The idea of developing UNIX was born from AT&T's Bell Laboratories in the early 1970's, the success of the UNIX operating system has led to many different versions. Until today, we have numbers of UNIX varieties and versions, like HP-UX, Solaris, Redhat, Suse not forgotten CENTOS, Fedora and others.

For more interesting UNIX history fact ... http://www.computerhope.com/history/unix.htm.  Its interesting, the fact shown that Linus Torvalds was actually born on the same year UNIX was being developed.