The British Library is the national library of the United Kingdom. The library is a major research library, holding over 150 million items from many countries, in many languages and in many formats, both print and digital: books, manuscripts, journals, newspapers, magazines, sound and music recordings, videos, play-scripts, patents, databases, maps, stamps, prints, drawings. The Library's collections include around 14 million books, along with substantial holdings of manuscripts and historical items dating back as far as 2000 BC. British Library is one of the two largest libraries in the world, the other being the Library of Congress of the United States.
More information on the Wikipedia page [1].
The website is [2].