PBS:

Have you decided that it’s high time to take a step back and look at the big picture? Is your teenager sick of your attempts to remember history class in your newly-founded home school? Or are you just desperate to watch a story that doesn’t include a certain word that rhymes with Arizona? Whatever your motivation, we’ve got you covered. All of these shows are available to watch right now without a membership. Just click the links and press play. Or better yet, find them in the free PBS Video app for your Roku, Apple TV, Samsung Smart TV, Fire TV Stick, phone or tablet. Enjoy!

Some of these are a bit old but still good info. Some are also available outside the US.