Dear All, Just wanted to share this excellent free Special Relativity online course I came across by Brian Greene, which I believe is one of the best around. Not sure if it's been shared before here. Special Relativity — World Science U, by Brian Greene http://www.worldscienceu.com/courses/university/special-relativity The lectures are clear and interesting, supplemented with intuitive animations, interactive demonstrations and excellent exercises (each question comes with a video to explain the answer). There's also a final exam, upon which you can obtain a certificate of achievement if you score 75% or more. Only problem is the interactive demos require a Wolfram CDF plugin, which doesn't work on most browsers anymore due to deprecated plugin technology. I found a temporary workaround for Firefox, where you have to install their ESR version, and the plugin will work (at least until early 2018). You can download it here: https://www.mozilla.org/en-US/firefox/organizations/ Happy learning!