A collection of online maps provided by Yale University Library. It seems it might require a plug-in to view them. It seems they are in the process of digitising even further so the collection should grow.
These are really useful - I use The "End" of Reconstruction in class because Prof. Blight lectures effectively on topics such as the 14th and 15th amendment, Frederick Douglass, precedent setting SC decisions such as Slaughterhouse & Cruikshank. Blight uses some humor and is a phenomenal storyteller who effectively links past to present.
YouTube is initially applying the captioning technology only to a few channels, most of them specializing in educational content. They include channels from universities like Stanford, Yale, Duke, Columbia and the Massachusetts Institute of Technology, PBS and National Geographic, and Google itself - its corporate videos will be captioned.