Bob's Pages
An interactive presentation of different geometric figures, including polyhedra, fractals, the arbelos, logarithmic spiral and Soddy's Hexlet.

The Complete Quadrilateral
An interactive column by Alex Bohomolny, discussing theorems and presenting illustrative demonstrations through java-enabled applets.

Diamond Theory
Description of new geometric theory, which reveals that Euclidean symmetry may be invariant under rather interesting groups of noncontinuous (and asymmetric) transformations.

Erich's Packing Center
Illustrated solutions to several covering, packing, and tiling problems. Includes some animated demonstrations.

The Geometry Center
A unified mathematics computing environment supporting math and computer science research, mathematical visualization, software development, application development, video animation production, and K-16 math education.

Geometry Formulas and Facts
Presents a document excerpted from the CRC Standard Mathematical Tables and Formulas (30th edition, 1995). Excerpt does not cover differential geometry.

Geometry in Action
Page collects various areas in which ideas from discrete and computational geometry (meaning mainly low-dimensional Euclidean geometry) meet some real world applications.

The Geometry Junkyard
A collection of geometry materials such as usenet clippings, web pointers, excerpts, papers, abstracts, programs and other materials that are entirely mathematical in nature.

The Math Forum: Geometry Research
Serves as a venue for academics to post research announcements, seminars, reviews and abstracts of papers. Also allows for the discussion of academic papers.

Mathematical Curves and Surfaces
A gallery of computer-generated mathematical forms using explicit, parametric, polar, cylindrical or spherical coordinates. Available in French and English.

Native American Geometry
Provides an in-depth look at ancient geometry which originates from a simple circle. Traces the history of the geometry that led to modern cultural symbols.

Packomania
Packings of objects in containers, including circles in a square, circles in a circle, or circles in rectangles. With downloadable source files.

Peek
Program for N-dimensional polytope visualization.

Wallpaper Groups
Provides illustrations and information on different plane symmetry groups.

Xah Lee's Home Page
Includes a visual dictionary of famous plane curves, illustration of common surfaces, information on discontinuous groups of rotation and translation in the plane, and projective geometry.