A good Error 404 page is perhaps as important as having great contents.
An Error Page is just a page that shows up when user tries to browse the page that doesn’t seem to exist anymore. The link may be broken, moved, or even it has never existed and never will. If a user hits such error page, it will do the best to help reader find what he is searching for; otherwise he will go away and may never come back. Check out this really well designed error pages to get inspiration for your own creative 404 page design.