The sitemaps protocol gives a webmaster an opportunity to inform search engines about all the URLs on your site that are ready for crawling. It is an XML file that assists Google, and other search engines, in locating the URLs for a site. Additionally, you are allowed to include any further information about each URL, like the last update date, URL changes and its importance/priority in regards to other URLs in the site. Sitemaps are hugely beneficial from an SEO perspective, especially in instances where a website has buried pages, few external/internal links, or areas of the site not listed via the on-site navigation.