The Light Cone: An Illuminating Introduction to Relativity
http://www.phy.syr.edu/courses/modules/LIGHTCONE/Introduces the basic principles of relativity, the physics of special relativity, and some basic principles of general relativity. Contains a great number of helpful images and animations; site created by Rob Salgado (Syracuse University).
Submitted in section: Physics: Relativity: The Light Cone: An Illuminating Introduction to Relativity