Thingiverse is a 3D design warehouse! This site has all sorts of great 3D models available for free download and use by your students.
Wisconsin 9/11 Memorial & Education Center
The Wisconsin 9/11 Memorial & Education Center’s website offers free lesson plans specific to teaching students in Wisconsin about the events of September 11th, 2001. While it is specific to Wisconsin, the lesson plans can be easily adapted for any location. The site also offers field trip activities and links