Or, in Net-Speak, publicdomainreview.org
There's a ton of stuff on here. Books, articles, whole movies, photographs, songs. Stuff both old and new, with the common thread being that it's all in the public domain.
I came across it by opening an article at Longreads.com. (dot org?)
Those are both great places to find six or eight thousand words about something that you had no idea was so fascinating. Or new information about something that you've been interested in for years, or in my case, decades.
It's all Kindlized within minutes. Happy hunting!