A Gallery of Interactive On-Line Geometry
   At the Geometry Center.
   http://www.geom.uiuc.edu/apps/gallery.html

Archimedes' Book of Lemmas
   A collection of all 15 propositions from Archimedes' Book of Lemmas with complete proofs, each accompanied by a Java illustration.
   http://www.cut-the-knot.org/Curriculum/Geometry/BookOfLemmas/index.shtml

Bette Veteto's Homepage
   History of Mathematics, very strong on geometry.
   http://www.people.memphis.edu/~brveteto/

Bob's Pages
   A collection of interactive geometry applets. Topics include polyhedra, Poncelet's porism, Soddy's hexlet, Mandelbrot set, Steiner porism, Pappus's chain, Repulsion polyhedra and stereo pictures.
   http://members.ozemail.com.au/~llan/

Conjectures Produced by the Program Graffiti
   Graffiti is a computer program that makes conjectures in mathematics and chemistry. Links to the conjectures and bibliography.
   http://cms.dt.uh.edu/faculty/delavinae/research/wowref.htm

Cuboid and Cube Surface Distances
   A java applet with substantial analysis related to distances on a rectangular box.
   http://www.btinternet.com/~se16/js/cuboid.htm

Cut the Knot
   Features articles about specific problems, illusions, and puzzles. Includes diagrams.
   http://www.cut-the-knot.org/geometry.shtml

Encyclopedia of Triangle Centers
   By Clark Kimberling. Over 1000 triangle centres in a searchable compilation with diagrams.
   http://faculty.evansville.edu/ck6/encyclopedia/

Erich's Packing Center
   Graphics and links for various packing, tiling and covering problems.
   http://www.stetson.edu/~efriedma/packing.html

Fundamentals of Geometry
   Free online book on geometry in pdf format. Contains material not easily found elsewhere from detailed exposition of elementary absolute geometry based on Hilbert's axioms to more advanced topics.
   http://polly.phys.msu.ru/~belyaev/geometry.htm

GLaD Comments
   A new type of geometric construction that was discovered by Dan Litchfield and David Goldenheim. Includes general explanation and sketch examples.
   http://jwilson.coe.uga.edu/Texts.Folder/GLaD/GLaD.Comments.html

Geometric Group Theory
   Information and resources about geometric group theory and low-dimensional topology. People, groups, meetings, links.
   http://www.math.ucsb.edu/~jon.mccammond/geogrouptheory/

Geometry Activities
   By Ephraim Fithian.
   http://homepage.mac.com/efithian/geometry.html

Geometry Center
   Web site for the (now closed) Center for the Computation and Visualization of Geometric Structures at the University of Minnesota. Graphics, multimedia, software, teaching resources.
   http://www.geom.uiuc.edu/

Geometry Formulas and Facts
   Excerpts from the 30th Edition of the CRC Standard Mathematical Tables and Formulas (1995), namely, the geometry section minus differential geometry.
   http://www.geom.uiuc.edu/docs/reference/CRC-formulas/

Geometry Page from Interactive Mathematics Miscellany
   Includes articles on topics in elementary and not so elementary geometry, many with interactive Java illustrations and multiple proofs.
   http://www.cut-the-knot.com/geometry.html

Geometry and the Imagination in Minneapolis
   Geometry exercises for a two-week summer workshop led by John Conway, Peter Doyle, Jane Gilman and Bill Thurston at the Geometry Center in Minneapolis, June 1991.
   http://www.geom.uiuc.edu/docs/doyle/mpls/handouts/handouts.html

Geometry in Action
   Includes collections from various areas in which ideas from discrete and computational geometry meet real world applications.
   http://www.ics.uci.edu/~eppstein/geom.html

Math 3210 - Higher Geometry I
   Course notes by Bill Cherowitzo.
   http://www-math.cudenver.edu/~wcherowi/courses/m3210/m3210.html

Math Forum: Geometry POW/POM Search
   Search the Geometry Problem of the Week's archive of creative, non-routine challenges, as well as submissions and commentary, dating back to 1993.
   http://mathforum.org/powgrepform.html

Math Forum: Geometry.research
   Discussion board for geometry professors and instructors to keep informed of the latest research.
   http://mathforum.org/kb/forum.jspa?forumID=130

Math Forum: Search geometry-forum
   Those interested in examining the previous incarnation of the Math Forum may search the archives of the Geometry Forum.
   http://mathforum.org/kb/forum.jspa?forumID=126

Mathematical Curves and Surfaces
   Graphical representations of computer generated forms. (French/English).
   http://perso.orange.fr/roger.assouly/

Morley's Miracle
   A discussion of Morley's famous theorem and the research of which it was a tiny part. 5 proofs are given including J. Conway's, D. Newman's, and A. Connes'.
   http://www.cut-the-knot.com/triangle/Morley/index.html

NPR : Mathematicians Get Crafty with Geometry
   A husband and wife from Cornell University have come up with a crafty way to illustrate high-level geometry concepts -- by manipulating yarn into models that help explain the curvature of spaces. The mathemeticians talk with NPR's Jacki Lyden about hyperb
   http://www.npr.org/templates/story/story.php?storyId=4531695

New Mathematical Findings by Secondary Students
   High school students solve complex geometric problems by using GLad Sketchpad. Page includes diagrams.
   http://www.javeriana.edu.co/universitas_scientiarum/vol6n2/ART1.htm

Packomania
   Includes packings of equal objects in containers together with source codes to obtain them numerically.
   http://hydra.nat.uni-magdeburg.de/packing/packing.html

Problem of the Minimum Rotation Surface
   Java applet demonstrating the catenary.
   http://home.ural.ru/~iagsoft/PMRS_J.html

The Complete Quadrilateral
   Several properties of the complete quadrilateral illustrated with Java applets
   http://www.cut-the-knot.org/ctk/CompleteQuadrilateral.shtml

The Entropy Reduction Laboratory by Karl-Dietrich Neubert
   Discusses double shell structured periodic systems, platonic spheres, molecular and crystal structures, and FlashSort algorithms.
   http://www.neubert.net/

The Geometry Junkyard
   Usenet clippings, web pointers, lecture notes, research excerpts, papers, abstracts, programs, problems, and other stuff related to discrete and computational geometry.
   http://www.ics.uci.edu/~eppstein/junkyard/

The Kepler Conjecture
   Information on the recent proof of Kepler conjecture on sphere packings.
   http://www.math.pitt.edu/~thales/kepler98/

The Lepidoptera of the Circles
   The Butterfly theorem and its generalizations illustrated by Java applets.
   http://www.cut-the-knot.org/ctk/Lepidoptera.shtml

Tim Lister's Hyperbolic Geometry
   Cabri constructions for the demonstration of the basic concepts of hyperbolic geometry in the Poincare disc model.
   http://mcs.open.ac.uk/tcl2/nonE/nonE.html

Wilson Stothers' Inversive Geometry and CabriJava Pages
   Includes Steiner's Porism and the arbelos.
   http://www.maths.gla.ac.uk/~wilson/cabripages/inversive/inversive0.html

Xah's Personal Page
   Features an illustrated dictionary of special plane curves, a paper on wallpaper groups, mathematics image gallery and links to software packages.
   http://xahlee.org/PageTwo_dir/more.html