You may think that the largest library in the world is in Europe, but you are wrong. It's in Washington, DC, the capital of the United States. People call it the Library of Congress. President john adams built this library for members of Congress. He hopes they can read law books here. The first batch of 740 books in the library were purchased from Europe. They put these books in the room where the Congress is meeting. Later, Thomas Jefferson sold many of his own books to the library during his presidency. He thinks that Congress should have books on various subjects, not just law books. This idea changed the Library of Congress forever, and the scale of the library is also expanding. Now it covers several hectares, with 20 million books and a lot of photos and movies. Experts in all fields work there. Every day, hundreds of people call to ask various questions, and many of them can get answers directly on the phone. The Library of Congress is like a big storage room. Thomas Edison's first film and Houdini's magic book are on display in the library. The Library of Congress has the best books in the world.