I recently came across the following resources online, that were new to me.
- Bookyards (Free, online books)
- Civil Rights Digital Library
- TV Lesson
- United Nations World Digital Library
They appeared in an article by Curtis Bonk, a professor at Indiana University. While Dr. Bonk teaches college students, he felt the R2D2 model (Read, Reflect, Display, and Do) model would be apropos for high school students. He recommended this sites as examples that can engage students with differing learning styles.