Harry Connick Jr. performs at the Library of Congress. (Justin Jouvenal/The Washington Post)

“This is all completely new to me,” he said marvelling. “I’m going to go home and play this stuff for my wife and kids.”

The Library of Congress and Sony launched a new Web site Tuesday that allows listeners to stream a vast archive of more than 10,000 pre-1925 recordings of music, speeches, poetry and comedy. Much of it hasn’t been widely available since WWI. Call it America’s iTunes.

Officials billed it as the largest collection of such historical recordings ever made available online. The Library hopes to add tens of thousands more songs to the “National Jukebox,” as it is dubbed, in the coming years.

Connick helped mark the occasion by playing “I’m Just Wild About Harry” on a piano during a press conference in a Library reception room. The jukebox hosts a version by composer Eubie Blake.

The collection, which is drawn from Sony’s back catalog, is a bewildering assortment of stuff. Listeners can hear the first ever jazz release — “Livery Stable Blues” by the Original Dixieland Jass Band — to 32 recordings of yodeling. There is a reading of the classic “Casey at Bat” and a forgotten speech by President William Howard Taft on U.S. policy toward Puerto Rico. Most of all, there is loads and loads of music: famed opera singer Enrico Caruso and composers Irving Berlin and George Gershwin are all represented.

“The absence of these recordings have created a sort of cultural amnesia. I think the jukebox will lead to a rediscovery of these artists,” said Patrick Loughney, who oversees the Library’s National Audio-Visual Conservation Center campus in Culpeper.

The jukebox allows listeners to create playlists of their favorite tracks and share them via Facebook or other sites. The Library is creating a series of playlists curated by historians and well-known artists.

Users can also thumb threw a virtual version of the 1919 version of the ”Victrola Book of the Opera,” which describes more than 110 operas, including plot synopses, illustrations and lists of recordings.

“These recordings are the foundation of the American sound,” said James H. Billington, the librarian of Congress. “They helped transform the musical landscape of the 20th century.”