You can view a web site as a virtual city sprawling down the sides of a hill, where the domain name is the center square, the URL’s are paths through the streets, and the pages are buildings. Some buildings are closer to the centre square than others, and some are connected to other buildings elsewhere in the city by side streets, tunnels, and alleyways — links.
When you visit different pages of one section of a site, you are walking between adjacent buildings. When you jump from one section of a site to another, you leap into the air and parachute down into a new neighborhood. Some buildings have links to entirely different sites, which is like stepping into a transporter beam that takes you to a somehow related building but in a different town.
To walk towards the centre of a city, you can manually edit a URL by deleting the right-most parts to walk up the side streets:
A similar process may be exercised on any Internet URL, although some addresses return a blank page because there is nothing yet built at that location. Most sites seem to have most of their buildings closest to the city center.