Tim Berners-Lee is the creator of the World-Wide-Web. He was working at CERN, a huge science centre in Switzerland, and there were already many ideas about this kind of thing around. Tim just pieced everything together, and there it was! He said the inventing bit was fairly easy- it was just getting people to agree with him that was the hard bit, and to join in.
How the World Wide Web just happened - Tim Berners-Lee
However, Tim Berners-Lee did not invent the internet- that is a whole different story! The world wide web is basically just how you compact al the information that was found on many different computers onto one massive web of info.