2- World History
3- PBS Teachers Social Studies
4- Social Studies Theme Units
6- Smithsonian Education
Smithsonian offers great resources on Art and culture, history and travel, science. From interactive Idealabs to homework help and many more.
7- Lesson Plans for Social Studies
8- Outreach World
Outreach World is an online community of educators dedicated to showcasing the achievements of its members and strengthening vital links across the education spectrum, and between the United States and the world.
9- Documentary Websites for Teachers
This is a collection of free websites that provides documentaries on a variety of different topics.
This is a set of free tools for teachers to create awesome timelines . Check them out .