| Recording_Consoles_of_the_20th_Century Contains pictures of most major recording consoles made in the 20th century. |
| Restoration_of_the_Leak_Stereo_20_Valve_Amplifier Provides information on circuit diagrams, parts listing, photographs and restoration advice. |
| World_of_Gramophones Downloads of historic recordings from cylinders and 78s as well as online sales of gramophones and recordings. |
| Yahoo!_Groups__AnalogueSynthesisers Discussion forum for information, classifieds, photos, and general know-how regarding analog and modular synthesizers. |
| 19th_Century_Music_restored_with_lasers New York Times Article: New technology designed to read cylinder records. (January 20, 2000) |
| Bridge_of_the_Month_Quiz An image is posted inviting entrants to identify the feature. A free copy of a book on the subject is awarded to one correct entrant per month. |
| Bridgepix_com Contains photographs and scans of other media of subjects worldwide. |
| The_Bridges_Project Online database of significant bridges compiled by the Department of Civil Engineering at Rice University. Includes photographs. |
| International_Peace_Highway_Project International Highway Construction Corporation, supporters of a highway system connecting most of the world which would include a Bering Strait bridge and Japan-South Korea tunnel. |
| MrTunnel_com Discusses many projects. |
| A_Span_For_All_Seasons A collection of photographs of facilities and a large worldwide inventory of suspension bridges. |
| The_Tunnel_Page The longest road and rail tunnels in the world, grouped by categories such as sub-sea tunnels and immersed tubes. |
| California_Freeway_Interchanges Photographs from around the state. |
| Continuous_Flow_Intersections Engineering firm page illustrating the connections in this feature. Includes illustrations and a video demonstration. |
| Highway_Feature_of_the_Week Large archive of maps and descriptions of unusual or complicated facilities, primarily in the United States. |
| Highway_Heaven_Blog Includes aerial photographs and commentary about certain features. |
| Highway-Intersections_net Compendium of map images from various European countries. |
| Images_of_Britain_-_Spaghetti_Junction The M6 at the A38(M) in Birmingham. |
| Interchange_of_the_Week Detailed entries for locations in New York State, using official state aerial photography. |
| Interchanges Page describing types found in the United Kingdom. Includes a link to the Bad Junctions page. |
| Interstate_Interchange_Browser Uses Google Maps to locate every interchange on the U.S. Interstate system. |
| Michigan_Left_Turn Describes how this unusual intersection feature works, including history. |
| Museum_of_Dumb_Highway_Design Aerial photos of and commentary on various interchanges which the author finds unusual or substandard. |
| The_Parallel_Flow_Intersection A specialized intersection. Page includes diagrams and research. |
| Unusual_Interchanges Diagrams and commentary of various ones in the East-Central U.S. |
| US_Highway_Interchange_Browser Covers Michigan and North Carolina. |
| An_VRML_rendering_of_the_15-91_interchange,_Corona_California_ A 4-level stack with one loop. Requires a VRML plugin to view. |
| WhereRoadsMeet Contains aerial photographs and descriptions of unusual or complicated facilities in the United States. |
| About_com__Letterboxing_and_Geocaching_Attract_Walkers Article describing the basics and the factors that motivate people to start letterboxing. |
| Aisling_Dart Artist from Salem, Massachusetts describes her boxes. |
| All_Info_About_Raising_Boys__Letterboxing_Family_Fun Brief article includes details on supplies and features instructions for participation with children. |
| Atlas_Quest_Letterboxing Trip planning portal offers clue search by country as well as tutorials and premium members services. |
| Brett_and_Penny\'s_Letterboxing_Page List of their boxes planted, found, and exchanged, primarily in Oregon and the Pacific Northwest. |
| British_Columbia_Letterboxes Introduction, photographs of personal stamps, and clues for boxes planted in southwest British Columbia. |
| Buckaroo\'s_Letterboxing Clues for boxes she planted in Washington and Massachusetts. |
| Catbead_Mischief Offering clues for letterboxes in the Syracuse, New York area. |
| Chowder\'s_Southern_California_Letterboxes Search for boxes in Long Beach, San Bernardino and Lake Arrowhead, California. |
| Chuck\'s_Letterboxing Chuck and Molly's letterboxes in Connecticut. |
| Connecticut_Department_of_Environmental_Protection__Letterboxing Official site supports letterboxing in publicly owned state forests. |
| Dartmoor_Letterboxes Introduction, tips and things to avoid, news, survey, and letterbox clues for the Dartmoor area. |