Teaching with Primary Sources

One of the Common Core elements is requiring students to better learn how to research, analyze, and use non-fiction sources including "Primary Sources" (original documents, text, books, photos, newspapers, etc).  Below is a selection of websites to help you with developing units of study that include primary sources.  I will be building this page as I find new resources.  If you find a good one, please let me know so I can add the page to this list. 

What are Primary Sources and Why Use Them?