If you need to make changes and need to take your sites offline for a little while, but don't want to just completely erase it, you can use the .htaccess file that catches all requests and directs them to one page, like so:
RewriteEngine on
Rewriterule ^(.*)$ http://example.com/construction.html [r=301,nc]
It will redirect all visitors to http://example.com/construction.html, obviously you'd fill in your own address instead of example.com.
