Search engines such as Bing, Google or DuckDuckGo can only access about 0.03 % of all the information stored on the Internet. Search engines compile their collection of websites available for searching by using crawlers, programs that gather information about web pages for their indexes. However, crawlers can't find information that needs to be accessed by a search interface, such as the Minuteman Library Catalog. Nor can crawlers find password-protected pages or web pages that aren't linked to any other web pages. These pages are what's known as the Invisible Web or the Deep Web. You can find information in the Deep Web using more specialized search tools. Here are a few below: Mednar.com Created by Deep Web Technologies, Mednar is a search interface for medical and health information that simultaneously accesses government sites, medical institutions, and mainstream media outlets. Just be warned that the number of search results can be overwhelming, especially if you don't limit your search to full-text retrievals. Archive.org This gem is a nonprofit online library of books, audio, and websites that is staggering in its variety. One section, the Wayback Machine, is an archive of defunct but often delightful websites. In the rest of Archive.org you can find items such as Somerville City Reports from 1843 to 1925, 1950s fallout shelter construction manuals, old community access television shows, and jazz recordings from the 1920s. The Life Picture Collection This searchable database of photos from Life, one of the truly iconic magazines of the twentieth century, includes work by some the greatest photographers of the time, such as Margaret Bourke-White, Alfred Eisentsaedt and Andreas Feininger. It's basically a mini-gallery of recent modern history: there are photos of Gandhi on the Salt March, Alexander Fleming in his lab, Mia Farrow hanging out with Frank Sinatra, and Martin Luther King praying at Selma. For fans of photography and history, this database is a treat. FindSounds.com This Parasonics corporation database is a searchable archive of sounds. I've found recordings of drums, harp music, tiger roars, beluga whale vocalizations, earthquake sounds and noises made by unspecified monsters: monsters growling, monsters moaning, monsters groaning. But this is 2015, and we all know goats rule the Internet (lolcats are so 2006). And they have lots of caprine recordings. This will get your goat: [audio wav="http://www.somervillepubliclibrary.org/blog/wp-content/uploads/2015/06/g..."][/audio] More from the Invisible Web in future posts.