The relativity pages of Prof. Franz Embacher, University of Vienna. A rich source ... oder
Clifford M. Will's page. A survey of the experimental tests of STR and GTR
The nice lectures of Michael Fowler for a wide public
Peter Breitfeld's scriptum for SRT and ART (in German) can be downloaded here
A lot of interesting material concerning relativity, supplied by the Max-Planck-Instituts for gravitational physics
A beautiful German Albert Einstein-page
The Einstein-pages of the American Institute of Physics
On the experimental tests of STR by Tom Roberts
Is time influenced by acceleration? Don Koks idea is that we need to introduce a special 'clock postulate' in STR to clarify this question. Experimentally the question seems to be settled.
Enjoy the visualisations created by the team of Ute Kraus, University of Tübingen
A selection of Harris' Cartoons on Einstein
The NOVA Einstein-page
The page of the University of Bremen (Germany) and its free falling tower. Click on Research and Facilities
A very detailed script of Norbert Dragon on STR and GTR. Certainly above high school level
"The Dummies' Guide to Special Relativity" by Arfur Dogfrey, "Dog School of Mathematics"
Michael Kramer and Andrew Lyne (University of Manchester) on their actual tests of GTR using the binary pulsars PSR J0737-3039A and -B . Title: "Einstein at least 99.5% right"
Nice JAVA-applets to do interactive work with Minkowski diagrams
Java-simulations on STR using Minkowski diagrams
Flash/Shockwave/... -animation on Epstein diagrams, gravitation may be turned on and off
A 'Short History of STR' with a lot of small Java applets