In trying to harden Apache on CentOS, you may feel compelled to remove the /manual from all of the websites your server is hosting. However the problem is, if you look in /etc/httpd/conf/http.conf you wont find "Alias /manual /var/www/manual"
If you try to add this your self you will get the following error:
The Alias directive in /etc/httpd/conf/httpd.conf at line 550 will probably never match because it overlaps an earlier AliasMatch.
The resolution is actually that the Alias for /manual is hidden in /etc/httpd/conf.d/manual.conf. You can comment out that file and you should now be good to go.