Most people use the terms "Web" and "Internet" interchangeably, but technically the Internet and the Web are two different beasts. The Internet is a global network of millions of computers that began in the late 1960s as a tool for university research and national defense. Information that travels over the Internet does so in a variety of languages (known as protocols.) Think of the many languages that are spoken over the telephone wires. In order to have true communication with the person on the other end, you both need to speak the same language. Technically, the Web (and its Hyper Text Transfer Protocol HTTP) is just one of the languages spoken on the Internet. Others include email, FTP (file transfer protocol), and Usenet news groups.
So the Web is just a portion (albeit a large one) of the Internet. It consists of multimedia (pictures, sounds, movies and words) viewed through a browser such as Netscape Navigator or Internet Explorer. The Web had its birth at CERN (Conseil Européen pour la Recherche Nucleaire) in 1989, but didn't start its explosive growth until 1993, when Marc Andreessen (then with the National Center for Supercomputing Applications) introduced Mosaic, the first graphical Web browser.