There’s a meme going around in conservative social media circles showing Margaret Sanger speaking at a KKK rally. The photo is fake. But... the reproductive rights activist really did address a meeting of KKK members in 1926.
Among the many science papers preserved online is the famous (and at one time, infamous) column written by Margaret Sanger. It only ran for a short while and was banned for obscenity, but now remains one of the more interesting historical documents out there.