Web pages (and web sites) are scattered all over the world, sitting on computers somewhere.
When you access a web site the "internet network" knows where the computer holding the web site is (Brazil, USA, Australia, Germany or wherever) and goes to get the web page or site.
It then downloads the web page or site to your PC so you can view it.
The internet is a bit like the phone system, but instead of a network of phones it is a network of computers.
If you think about it, there may be a phone sitting doing nothing in say Australia, but if you dialled the right combination of numbers it would ring.
Same with a web site. There may be a web site sitting on a computer in Australia, but if you put the right address in, then the computer in Australia "wakes up" and sends the web page to you.