About.com page gathers together information about mysterious booms, persistent hums, and underground rumblings that defy explanation. Includes audio clips.

Article about the Moodus (Connecticut) noises and the findings of recent investigations that linked these noises with seismic activity.

Investigation into the cause and adverse health effects of the Bristol Hum, an obnoxious low-frequency noise heard in England. Conclusion is that the hum is due to a pulsed electrical signal.

Discussion of research into the physics behind mysterious sounds resembling cannon fire, heard at Barisal, India, and other locations around the world.

Information and links about the "Taos Hum," a low throbbing sound heard in quiet locations worldwide, especially in the USA, UK, and northern Europe. It is not detectable by microphones or VLF antennae, and the source is still a mystery.

Yahoo Group for discussion of mysterious hums.