This is a high-res image which takes up much more than the screen. Scroll around to view different areas. Also, in most browsers you can zoom in and out on a page using the Ctrl-plus and Ctrl-minus hotkeys (Mac users use Command key instead of Ctrl). Ctrl-zero returns the page to normal size. Using this technique you can look at the map in different levels of detail. Of course, you can also download it to your computer and view it even more easily.
Click numbers in the small map at upper-right to go to different sections without returning to overview page.