The Library of Congress has put two of its photographic collections on Flickr, a public photo sharing site. This purpose of this pilot project is:

firstly give you a taste of the hidden treasures in the huge Library of Congress collection, and secondly to show how your input of a tag or two can make the collection even richer.

Flickr users are invited to help describe these 1500+ photos by adding tags and leaving comments. The collection is available at http://flickr.com/commons. Take a look and try adding a few tags.