The World Digital Library (WDL) is a joint project of the U.S. Library of Congress, UNESCO and libraries, museums, and educational partners worldwide. Its catalog includes primary sources, such as books, maps, manuscripts, photographs, and more from all countries and cultures. It is accessible in Arabic, Chinese, English, French, Russian, Spanish, and Portuguese.
The British Library offers digital access to its rare books collections, including the Magna Carta, and introductions to many topics from history and literature.
Find images, archival material and explorations of many scientific topics from the American Museum of National History.
Open Library, a non-profit project, aims to catalog on the web “every book ever published” and to provide access to electronic versions whenever available.
UNESCO Open Access Publications is a portal for “resources on literacy, gender, youth, environment, arts and other disciplines directly and indirectly related to development issues”.
Open Culture collects “the best free cultural & educational media on the web” including online courses, movies, audio books, ebooks, and language learning material. New resources and interesting links are published on their Facebook page.
Project Gutenberg currently gives access to 46,000 free quality ebooks, mainly in English but also in German, Italian, French and Portuguese. New resources and interesting links are published on their Facebook page.