The Invisible Web, or Deep Web, includes all information not indexed by search engines, such as disconnected pages, password-protected sites, and real-time content, with experts estimating it comprises up to 75% of the internet. Accessing the Deep Web typically requires specialized tools like Tor, which ensures anonymity and allows users to browse various hidden services and potentially illegal content. While it contains valuable resources such as banned books and educational materials, the Deep Web also poses significant risks including phishing and exposure to harmful content.