"This archive of primary documents from World War One has been assembled by volunteers of the World War I Military History List (WWI-L). International in focus, the archive intends to present in one location primary documents concerning the Great War."
Another one of the precious collections provided by that most excellent of libraries, Harvard University Library. It's so great that they don't just lock it up and be snobs. Good on them.
Women Working, 1800 - 1930 focuses on women's role in the United States economy and provides access to digitized historical, manuscript, and image resources selected from Harvard University's library and museum collections. The collection features approximately 500,000 digitized pages and image
An innovative and useful site. It presents historical events as news stories with a depth of information that is impressive. Written in a lively manner, this would be suitable for high school class activities or even student research. They provide their references.