Royalty free video company, Pond5, recently launched the Public Domain Project in which they digitized almost 80,000 copyright free video clips, audio recordings, photographs and 3-D models for use of the public. Among this collection includes famous speeches from Martin Luther King, Jr., classic silent films like A Trip to the Moon and photographs from the first lunar landing among thousands of others. This is a great resource for use in creative projects without having to worry about copyright.
You can access the archive at this link.