Making a Content Window with a Bookmarkable Location

I'm creating a website with that same basic design we see in every webpage:

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Logo

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Navigation Bar
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Content Window



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I've got a great logo, navigation bar, and content all written in HTML/CSS...
What I want is for my webpage to load.
But when a link is clicked on the Navigation Bar, it just reloads the Content Window.
An Iframe would do that obviously.
But I also want each location in the website to be bookmarkable; meaning I want the URL to reflect the current location of the content window.
At least the way I know how to use an IFrame when the user clicks the navigation bar, the URL doesn't change.
Any suggestions?
Also I don't mind adding on other webprogramming schemes aside from HTML/CSS so if you're like this only works if you use JavaScript, I can do that.