The Brittinghams were a prominent and influential family in Wisconsin. This collection of more than 1,600 images consists of their personal and travel photographs taken between the years 1897 and 1922. These images "capture the private lives of a wealthy family at the turn of the century, and document their travels to 22 states and 32 countries." The wide variety of subjects includes family life, social life, the Brittingham homes, and various scenes from around Wisconsin. More than 750 slides picture international locations. The site also offers an interesting collection of slides that picture forms of transportation encountered by the Brittinghams, including airplanes, sailboats, streetcars, trains, carriages, and sedans.

The collection can be browsed in its entirety or by pre-selected subjects (Wisconsin, Brittingham family, social life, international travel, interiors, or transportation). Visitors can search the slide collection by using the guided search option and selecting Brittingham Lantern Slides in the drop-down menu. For those researching the lives of the well-to-do in the U.S. at the turn of the century or, more generally, the social and cultural history of Wisconsin or the U.S. in the early decades of the twentieth century, this collection of images is a useful resource.

A collaborative effort between students and faculty at Bowling Green State University in Ohio, this site includes two sections. In the first, a timeline from 1888 to 1899 provides, for each year, snapshots of major national events, personalities, and statistics as well as excursions to approximately 30 additional links, background essays, images, quotations, bibliographies, and other material. The second, "Bowling Green, Ohio: A Tour of the Crystal City," contains 27 photographs; a month-by-month timeline covering town events during the years 1892-97; a 19,000-word essay written in 1897 on Bowling Green's "early history"; and essays ranging from 1,500 to 3,000 words on specific topics. No search engine, but the site may be browsed by year. Useful both as a general overview of the period and as a local history resource.

This site was created by Idaho State University professors Mike Trinklein and Steve Boettcher as a companion to their PBS documentary, The Oregon Trail. The website describes the history of the Trail and the settlers who used it to migrate to the Oregon Territory beginning in the early 1840s. It is divided into five sections: general information about the history of the Oregon Trail; historic sites along the Trail; facts and statistics; full-text archive; and "Shop the Oregon Trail." The archive includes full texts of seven diaries, two letters, nine memoirs, and five period books about journeys along the Trail.

The site also contains roughly 30 video clips of historians discussing the history of the Trail and a virtual field trip of the Trail's top sites. There is an online teacher's guide that was designed as a companion to the documentary video, but its discussion topics and activities can be adapted for classroom use. The site is easy to navigate and has a keyword search feature.

These 181 firsthand accounts of North American and Canadian exploration range from Viking stories such as The Saga of Eric the Red from circa 1,000 CE to journal entries written in the early 19th century on a trapping expedition in the Southwest. Documents include the Original Journals of the Lewis and Clark Expedition, 1804–1806. Materials include rare books, original manuscripts, and classic travel narratives.

Users can browse the full archive or by expedition, settlement, geographic region, and U.S. state or Canadian province. Each document is individually searchable and accompanied by a short background essay and a reference map. There are also 150 images available, including woodcuts, drawings, paintings, and photographs. Highlights follows the collection chronologically and connects moments in American history with eyewitness accounts.

In conjunction with the Russian State Library in Moscow, the National Library of Russia in St. Petersburg, and the Rasmuson Library of the University of Alaska in Fairbanks, the Library of Congress has digitized more than 2,500 items, comprising approximately 70,000 images, and provided transcriptions and commentaries in English and Russian to offer a comparative history of American and Russian expansion through frontier territories in each nation's continent. The site presents an overview of expansion into Siberia and the American West in six sections: Exploration, Colonization, Development, Alaska, Frontiers and National Identity, and Mutual Perceptions. Each section contains from two to 11 modules that call attention to similarities and differences between the two histories with regard to subjects such as migration—forced and otherwise, missionaries, religious flight, mining, railroads, agriculture, cities, popular culture, and tourism, and even compares Cossacks with cowboys.

The site offers more than 40 complete books, including manuals, handbooks, fiction, and travelers accounts; 77 maps and one atlas; 438 items from the Russian-Ukrainian Pamphlet and Brochure Collection; materials from six complete manuscript collections, regarding exploration, trade, and commercial activities; four tour-of-the-century films; 125 newspaper articles; 11 dime novel covers; five photographic collections; and one sound recording of a Russian folk song. Provides a 500-title bibliography and links to 30 related sites. Valuable for those studying the American West and Russian history and investigating ways to explore frontiers of comparative histories in order to expand beyond limits of national history narratives. Listen to the audio review: .

This website provides materials published for the 1933-34 World's Fair including copies of official publications, press releases, souvenir albums, guidebooks, maps, brochures, postcards, photographs, and newspaper clippings. Users can search the checklist of the Official Publications of the Century of Progress International Exposition and Its Exhibitors containing over 1,225 items, some 350 of which are available online. The checklist can also be browsed by author, title, or subject. Additionally, the site provides links to websites related to the 1933-34 World's Fair.

An extensive site covering the history of NASA's aeronautical and space programs. Materials include photographs, flight communications transcripts, essays, timelines and chronologies, policy documents, biographies, and much more. "Aeronautics" includes flight research centers, flight research projects (such as the lifting body program and the X-1 that first broke the sound barrier), and the X-15 project. "Biographies" includes all present and former astronauts. "Human spaceflight" offers extensive material, including essays, technical information, and other material on the Mercury, Gemini, Apollo, Skylab, Apollo-Soyuz Test Project, and Space Shuttle projects. The Apollo Program includes the Apollo Lunar Surface Journal, an extensive site that provides corrected transcripts of recorded conversations between lunar surface crews and mission control with commentary from the site editor and 10 of the astronauts who walked on the moon. The same is available for Apollo 12, 15, and 16 Flight Journals. Reference material includes more than 50 historical policy documents including NASA's 1959 Long Range Plan and the 1986 Report of the Presidential Commission on the Space Shuttle Challenger Accident. There are more than 30 timelines and chronologies.

The photo and video section has video clips from the Apollo missions including lunar surface exploration. The massive Johnson Space Center Digital Image Collection has a searchable database of more than 9,000 NASA press release photos from the manned space program (Project Mercury to the Space Shuttle). "Space science" includes descriptive information and technical data on all planetary exploration projects from Mariner and Pioneer to Voyager and Galileo, as well as the lunar probe series Ranger and Surveyor. "NASA History for Kids" includes more than 25 links to sites for elementary and middle school students' research. With a wealth of both primary source material and secondary source information this site is an outstanding resource for teaching or researching the history of aeronautics and astronautics and the history of U.S. science and technology in the 20th century.