My favorite state-library resource for teaching materials

The Library of Virginia's Online Classroom is my favorite state-library resource for teaching materials.

The Classroom is divided into five features:

1. The Document Bank of Virginia offers a selection of photographs, diagrams, maps, and printed materials organized into ten historical eras.  Each era's section begins with a helpful explanatory essay.  The entire is collection is searchable with three handy tools.
2. The Guide for Educators is an overview of the Library's vast collection for classroom teachers.
3. Shaping the Constitution contains seven lessons about key events in constitutional history, from the Revolutionary Era to ratification of the 19th Amendment's women's-suffrage guarantee.
4. Union or Secession offers materials and lesson plans about Virginia's decision to join the Confederacy.
5. The Lessons Plan section collects all the Library's teaching materials in one spot.  (Materials here are presented in random order.  I've written to the Library, asking them to list each lesson in chronological order.)

These materials would be engaging and informative for students anywhere.  (Full disclosure: I live and teach in Virginia.  But the topics discussed appeal to a general audience of U.S. History students and teachers.)