The Animal Diversity Web is an online database and encyclopedia of animal natural history, built through contributions from students, photographers, and many others.
Free, online, resources to learn Spanish (or English) words in a fun way. Each word in the dictionary has an English and Spanish translation and transliteration and a photograph of the item. The interface is simple and both kids and adults will find this educational website entertaining and useful.
A wonderful source that combines an almanac, dictionary, and encyclopedia. It includes biographies of the United States Presidents. This page allows you to search through the entire archive of the site. Every day there is an interesting link to events in the past from primary source materials in the Library of Congress.
This site focuses on the exploration period. It has a search engine for images. Under a link for "Historical Highlights" you can find a timeline of exploration.
This is a wonderful collection from the Library of Congress. Resources available on this site include: manuscripts, texts, sheet music, maps, motion pictures, photos, prints, and sound recordings.