The Great 78 Project is a community project for the preservation, research, and discovery of 78rpm records. From about 1898 to the 1950s, an estimated 3 million sides (~3 minute recordings) have been made on 78rpm discs. While the commercially viable recordings will have been restored or remastered onto LP's or CD, there is still research value in the artifacts and usage evidence in the often rare 78rpm discs and recordings.
Thanks now to the Internet Archive, that stalwart of digital cataloging and curation, we can play twenty five thousand 78s and immerse ourselves in the early 20th century, whether for research purposes or pure enjoyment.
Peep the archive here.