wget \
     --recursive \
     --no-clobber \
     --page-requisites \
     --html-extension \
     --convert-links \
     --restrict-file-names=windows \
     --domains domain.com \
     --no-parent \
         www.domain.com/html/

This command downloads the Web site www.domain.com/html/.

The options are:

• recursive: download the entire Web site.
• domains website.org: don't follow links outside website.org.
• no-parent: don't follow links outside the directory html/.
• page-requisites: get all the elements that compose the page (images, CSS and so on).
• html-extension: save files with the .html extension.
• convert-links: convert links so that they work locally, off-line.
• restrict-file-names=windows: modify filenames so that they will work in Windows as well.
• no-clobber: don't overwrite any existing files (used in case the download is interrupted and resumed).

Source