The Wayback Machine is a digital time capsule created by the Internet Archive, a non-profit organization, based in San Francisco, California. It is maintained with content from Alexa Internet. The service enables users to see archived versions of web pages across time, which the Archive calls a "three dimensional index".
The name Wayback Machine is a reference to a segment from The Rocky and Bullwinkle Show in which Mr. Peabody and Sherman use a time machine called the "WABAC machine" (pronounced "Wayback") to witness, participate in, and, more often than not, alter famous events in history.
Check out Wayback Machine @ www.web.archive.org